Monday, December 31

Dermis - Reticular layer of dermis

Home > Know your skin > Dermis > Reticular layer of dermis
In dermis, reticular layer lies below the papillary layer. Reticular dermis is the deepest part of the skin and lies superficial to the hypodermis.
Reticular region, ranging from 1-3mm in thickness, is much denser and thicker than the papillary region.

Dense irregular connective tissue and adipose tissue are the  major constituents of this region. Fibroblasts (fiber producing cells) and adipocytes (fat cells) abound this reticular region. It has densely packed thick collagen fibers, elastic fibers and reticular (netlike) fibers giving skin structural and tensile strength, elasticity and extensibility. These fibers are arranged in parallel to the surface of the skin. The reticular fibers (reticulin), made of Type III collagen, weave throughout reticular layer giving a net-like appearance and hence the name.

Most of the important epithelial glandular structures of skin like eccrine (sweat) glands, apocrine (scent) glands and Sebaceous (oil) glands are located here.

Blood and lymphatic vessels are found traversing this region carrying nutrients, oxygen and immune cells. The deeper vasculature to the skin, the deep cutaneous plexus, are located at the junction of reticular region and hypodermis.

The hair folicles and nails are located in the reticular layer. The 'arrectores pilorum' muscles are located here attached to individual hair follicle. They are responsible for  piloerection and produce goose bumps or cutis anserina. They are innervated by the sympathetic branch of the autonomic nervous system.

Nervous tissues and receptors are located in this area transmitting sensations like pain, cold and heat and make skin sensitive to touch. Special nerve cells like Meissner's, Vater-Pacini and Pacinian corpuscles are found here. They are responsible for transmitting the sensations of touch and pressure.

The criss-crossing collagen fibers form Langer's lines, also called as cleavage lines. They correspond to the natural orientation of collagen fibers. Surgical incisions made parallel to Langer's lines may heal better, faster and produce less scarring than those cutting across the fibers. Any damage to reticular layer of dermis can cause scarring.
Image source: http://en.wikipedia.org/wiki/File:Normal_Epidermis_and_Dermis_with_Intradermal_Nevus_10x.JPG
Author: Kilbad
License: public domain

Current topic in dynamic skin care: Reticular dermis layer.

Sunday, December 30

Hypodermis layer - Function of hypodermis

  ›   Hypodermis layer - Hypodermis function
Hypodermis, also known as subcutaneous tissue, has important functions. Hypodermis layer lies immediately below the dermis.
It is the lowermost layer of our integumentary system. Though hypodermis is not part of the skin, it is very essential for anchoring the skin to the body. Though both dermis and hypodermis are derived from mesoderm, unlike dermis, this layer is not derived from dermatome region.

Subcutaneous tissue layer has many types of cells in it like fibroblasts, fat cells (adipocytes) and leukocytes. Fibrous bands and elastins are found in this region of integumentary system, anchoring the cutaneous layer (skin) to the deep fascia fat. Sudoriferous glands (sweat glands), papilla region of hair root and pacinian corpuscle (a type of nerve ending) are found in the junction of dermis and hypodermis.

Blood vessels and lymphatic vessels traverse this region, carrying the blood and lymph to the dermis. At the junction of dermis and subcutaneous tissue, arteries form deep cutaneous plexus. Its function is to supply oxygen and nutrients to the tissues in the hypodermis, dermis, hair follicles, sebaceous glands and sweat glands.

The thickness of hypodermis varies considerably in respect of body area, nutritional status, age and gender of the individual. In thin areas of the skin like eyelids, genitals, and nipples, it is nearly absent. With aging drastic changes take place in the hypodermis. It begins to thin out and disintegrate causing deep wrinkles, folds and sagging of the facial skin.

The fat storing cells, adipocytes, are grouped together in lobules separated by connective tissue. Hormones in adults have effect on the pattern of hypodermis fat distribution function. In men fat tends to accumulate over the abdomen, torso and shoulders and in women fat accumulates on the breasts, waist, hips, buttocks and thighs. In weight loss there is usually changes in the amount of lipid content of the adipocytes and not in their number.

The adipose fat also functions as a cushion and padding against pressure and friction, absorbing shocks from impacts to the skin. Fats stored in this layer also functions as energy reserve and the fat is put back into circulation when needed. Another function is in providing thermal insulation to the inner body to slow down heat loss. This helps in the regulation of body temperature. Children and elderly people have less storage of adipose fat in their subcutaneous tissue and are more sensitive to cold.

Panniculus carnosus, a layer of flat sheets of striated muscle is found in hypodermis. Their function in humans is seen in some muscles of facial expression, dartos muscle (dartos fascia or tunica dartos) lying beneath the skin of scrotum, palmaris brevis muscle in the ulnar side of hand and platysma muscle found in the neck.
In many regions of hypodermis vestigial panniculus carnosus is present and is usually covered by panniculus adipose fatty layer. The function of elastin fibers found in the hypodermis layer is in giving elasticity to skin Image source: http://en.wikipedia.org/wiki/File:Skin.png
Author: US-Gov
License: Public domain.

Current topic in dynamic skin care: Functions of hypodermis layer.

Saturday, December 29

Skin types - Different types of face skin

Home > Different face skin types
There are five basic different face skin types seen in the general population. For proper skin care and beauty enhancement you have to know and identify these different types to make right decisions.
Use of wrong skin care products in fact can be disastrous to your face skin.

Factors contributing to different face skin types

Different seasonal weather conditions and atmospheric and environmental factors have effect on your skin. The hormones produced by your body and the genetic and hereditary factors can have a lasting effect on the skin. Mental and physical stress, emotions, your food habits, general health conditions and aging can contribute to your having any particular condition.

The types of different beauty products and topical applications so far used have a direct bearing on your epidermis. There may be a constant state of fluctuation of the types and the situation may change from one to an entirely different one even in a weeks time. Hence periodic testing for your face condition is necessary.

Different face skin types

There are basically five different conditions. They are,
  • normal,
  • oily,
  • dry,
  • combination and 
  • sensitive.

Normal face skin

This is an ideal condition, least common and a very small percentage of people have it. The truth is that such people will be having an excellent state of overall health. Normal skin is smooth to touch and is not oily, shiny or dry. It has even tone and complexion and appears healthy with fewer blemishes. This type has small pores and balanced levels of natural oils and moisture. It is firm and elastic showing few wrinkles. Taking care of such dermis is easy and requires only some protective applications. Overdoing any cosmetic procedures may in fact ruin and change this condition.

Oily condition

The skin of the person with this condition, especially on the face, appears shiny and oily and has enlarged pores.
The individual with this condition is very much prone to acne, blackheads and whiteheads. Oily condition is more common in teenagers and young adults in twenties. Due to hormonal inducement, sebaceous glands secrete excess sebum in this age group. Though the whole face gets oily, the "T" area of the face, namely neck, chest and back are more affected.

Dry condition

Skin in this condition is chronically dehydrated. It appears dry, flaky and parched with small pores. It is tight, dull and leathery in appearance and sometimes wrinkles begin to appear. Loss of moisture and natural oils leads to this condition. Excessive exposure to sun or cold winds, aging, nutritional deficiencies, recurrent infections and inappropriate use of cosmetics can cause or aggravate this problem. Different dry dermal care efforts are necessary to get relief. Elderly people quite often suffer from this condition.

Mixed or combination types

Many people have this condition with mixture of normal, dry and oily skin. Forehead, nose and chin area of the face is known as "T" zone. This area appears oily with enlarged pores. Cheeks, sides of the forehead and neck may progressively be normal or dry. In beauty care and treatment different types of products have to be used in this condition. Dry areas may require moisturizer whereas oily areas may require products like cleanser to remove excess oil.

Sensitive skin types

In this condition dermis is usually thin and fine textured. Rashes and redness may appear as allergic reactions to cosmetics, sun and cold exposure. These mild to severe reactions may leave it sore and dry. In order to protect this condition of face it is advised to wear sunscreen when going out. Beauty care products which do not have harsh chemicals and have only natural substances are best suitable.
Image source: http://upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Hair_follicle-en.svg/500px-Hair_follicle-en.svg.png
Author: User:Helix84
License: Public domain
Current topic: Different facial skin types.

Friday, December 28

Skin facts - Main functions of human skin

Home > Main functions of human skin
Human skin has the major function of protecting the internal organs from external elements.
Being an organ of regulation, skin regulates several aspects of human physiology like fluid balance, body temperature, vitamin D synthesis, peripheral circulation, desquamation and immunological surveillance. Being an organ of sensation, human skin detects and relays main senses like heat, cold, touch and pain with the help of network of nerve cells present in it.

Barrier and protection

Being the natural barrier, skin protects the internal organs of the body from exposure to the natural elements and pathogens. Further it provides mechanical support to the body by covering and holding together the internal organs.

One of its main functions is two way water proofing. In normal healthy conditions it neither keep absorbing water and bloating nor losing water continuously and dehydrating. The natural layer of lipids, oil, cross linked keratin, corneocytes, salt and lipids from sweat and sebaceous secretions present on the outermost surface is the main defense from attacking bacteria and viruses.

Desquamation and self-healing

The outer layer of human epidermis is prone to physical damage and it has to be repaired continuously. It is continuously renewed by cell proliferation at dermis level and in epidermis the  outer most layers undergoing desquamation.

UV protection

The melanin pigment present in the skin, by filtering the Ultraviolet rays to some extent, protect it from sun damages and cancer.

Thermoregulatory functions

Sweat glands present in the human skin produce sweat (perspiration) in hot conditions.
By the effect of latent heat of evaporation it is cooled when the sweat evaporates.

Radiation

Excess heat from the body, as in the case of exercise or having fever, is radiated by the skin to the surroundings to stabilize and bring the body temperature down.
This is brought about by increase in blood supply to the dermis and dilation of dermal blood vessels.

Insulation functions

The human skin insulates the body to great extent by not allowing the body to lose heat and absorb cold from the surroundings.
Further by constriction of dermal blood vessels lesser amount of blood flows to dermis and heat loss is reduced.

Immunological surveillance

There are numerous specialized Langerhans cells present  which can identify harmful proteins and substances and take them to white blood cells and neutralize them.

Sensation

To bring about one of its main functions, nerve endings and special nerve cells in it contribute to the sensations like touch, pressure, vibrations, pain, cold and heat.
Though there are millions of nerve endings in it, their main concentration differs at different regions of the human body and some regions are very sensitive.

Main absorption functions

Skin can take in and/or release small amounts of gases like oxygen, carbon dioxide and nitrogen.
Oxygen is taken in and carbon dioxide is released out in small quantities to help in respiration.
Its absorbing capacity is utilized to send in medicines in the form of ointments and patches.
Various skin care and cosmetic products also get absorbed through it.
The main absorption functions can be either trans-cellular or inter-cellular.

Excretion

One of its main functions is the excretion of metabolic waste products and toxic substances like salt and urea.

Vitamin production

In humans, vitamin D synthesis is one of its main functions and in the presence of UV rays by chemical interactions with a naturally occurring lipid known as ergosterol, vitamin D is produced.

Storage functions

Lipids and water are stored in the epidermis to control loss of moisture from the body.
Excess lipids in the system are stored in the human skin.
Image source: http://en.wikipedia.org/wiki/File:Skin.png
Author: US-Gov
License: Public domain.

Current topic: Main functions of human skin.

Thursday, December 27

Skin facts - Know your skin

Home > Skin facts - Know your skin
Do you know that your skin is the largest organ in human body? In fact if you are an average adult, its surface area including hair, nails and glands, may measures about 1.5-2 square meters (about 17-22 square feet) and weigh about 3.5 kilograms (about 8 pounds).
Your radiant and glowing skin, in fact, is a very complex structure made up of millions of different types of cells carrying out many varied functions.

Know the structure of your skin

Skin is a dynamic organ in a state of constant change. The layer which is visible to us is in fact dead layer in the process of desquamation (shedding). It is made up of two layers. The outer most of layers is called epidermis and the inner or deeper layer is called dermis.

The epidermis in fact has the outer dead and dying layer and inner rapidly dividing layer. The epidermis on its outer side is mostly made up of flattened dead cells about to be shed off. The inner epidermis consists of rapidly dividing keratinocytes, pigment cells and nerve endings.

The dermis in fact is composed of two layers namely the papillary and reticular dermis. Apart from collagen tissue, elastic fibers and extra-fibrillar matrix make up the structural components of the dermis which give your skin its strength and flexibility. The dermis layer is also interspersed with blood vessels, nerves, hair roots and sweat glands.

Hypodermis, also known as subcutaneous fascia, lies beneath the dermis and is responsible for binding epidermis and dermis to the body. The hypodermis has connective tissue, sweat glands, fat cells, larger nerves, blood vessels and collagen producing fibroblasts.

Know the functions of your skin

Do you know that skin functions as a barrier. In fact it protects the internal organs and muscles from loss of body fluids and also from environmental elements and pathogens. it also has a thermoregulatory function by which the body temperature is maintained both in hot and cold conditions. Senses like hot, cold, touch, pressure and pain are picked up by millions of nerve endings present in it and are conveyed to the brain. Do you know that dermis synthesizes vitamin D on exposure to ultraviolet rays present in the sunlight?

Know your skin tone (color)

The melanin pigment and its type determines the color of a person. In excess presence melanin can give black color whereas its total absence in the dermis as found in certain genetic disorders can give rise to albinism. Blond hair, red hair and color of the iris are the effect of the proportion, density and types of melanin present.
In the same person melanin is concentrated at different levels producing pink lips, whiter palms and soles and white of eyes.

Know your skin type

Cosmetologists have categorized skin types into normal, oily, dry,  combination and sensitive types. The first three types can be easily known. In the combination type oiliness is only on the forehead, nose and chin areas and it appears dry in the rest of the body. When sensitive, it appears smooth in structure and is very reactive to environmental elements and chemicals. Further all of us know that its thickness differs and it is thinnest on the eye lids and thickest on the soles of the feet.

Healthy skin can only be present in a healthy body. It is an indicator of general status of your health. Nourishing and nurturing the body properly will give you true beauty. Poor internal health reflects as acne, wrinkles, blemishes, spots, premature aging, inflammation, infections, allergies and cancer.  Avoiding consumption of unhealthy foods and adding sufficient amounts of fruits and vegetables will improve the general health and give your skin radiance and glow.
Image source: http://en.wikipedia.org/wiki/File:Skin_layers.svg
Image author: Madhero88 and M.Komorniczak
License: CC BY-SA 3.0
Current topic: Skin facts - Know your skin.

Wednesday, December 26

Nourishing skin - Fruits and vegetables for healthy skin

Home > Nourishing skin - Fruits and vegetables for healthy skin
Nourish your skin from within by eating fruits and vegetables as healthy skin starts from inside. For a lasting smooth clear complexion and a healthy glow of your facial skin incorporate different fruits and vegetables into your diet on a daily basis.

The Center for Nutrition Policy and Promotion, of the U.S. Department of Agriculture, recommends including half of our food plate with fruits and vegetables to get nutrients vital for the health and maintenance of our body. Following the guidelines will nourish us fully. Women are advised to include 2½ cups of vegetables and 2 cups of fruits in their daily diet. Men are advised to incorporate 3 cups of vegetables and 2 cups of fruits in their daily diet. This requirement pertains to 19-30 age group. In elders (50+) half a cup may be reduced from the requirement of 19-30 age group.

What do fruits and vegetables contribute for nourishing skin?

Vegetables and fruits are naturally low in fat and calories and none have cholesterol. However they are rich in essential nutrients required for nourishing skin. They are actually good sources of less consumed nutrients like potassium, vitamin A, vitamin C, vitamin B complex, dietary fiber and many other trace minerals.

Fruits and vegetables are rich in dietary fiber required for the digestive system. Dietary fiber also reduces blood cholesterol, increases the bowl movement and reduces obesity. The dietary fiber content in vegetables and fruits helps in increasing the flow of amylase enzymes, enhancing the digestive process. Lack of dietary fibers leads to constipation. Incomplete bowel evacuation produces toxins and causing flare-up of pimples and acne on the facial skin. Obesity leads to fat deposits under the dermis layer and causes stretch marks.

Potassium is present in banana, prune, peaches, apricots, cantaloupe, honeydew melon, and orange. It is also present in sweet potatoes, white potatoes, white beans, tomato, beet greens, soybeans, lima beans, spinach, lentils and kidney beans. Potassium helps to maintain healthy blood pressure and proper blood supply required for nourishing skin.

Vitamin C present in citrus fruits nourishes body cells and helps in increasing the blood flow to skin. Vitamin C also helps in collagen synthesis which is required for skin growth, repair and elasticity. It is also important for protection from chronic skin diseases and in healing of cuts and wounds. Vitamin C also helps in iron absorption essential for red blood cell production and function. Oranges, grapefruit, lemons and limes contain high levels of nourishing vitamin C.

Vitamin A is essential for the eye function as well as nourishing skin. It is also a potent antioxidant protecting our skin from free radicals which can cause premature aging. It is also helpful in the control of acne.

Like vitamin A and vitamin C, vitamin E is also nourishing and is a potent antioxidant helping in the protection of cells from the oxidative damages caused by free radicals.

Vitamin B complex, consisting eight vitamins is essential for cell division and cell proliferation. They also help in the maintenance of blood circulation and delivery of nutrients for the skin. Their deficiency can lead to dry and cracked skin, eczema, pimples, skin discoloration and wrinkles.

Trace mineral like zinc are very essential for nourishing skin. Its deficit leads to hair-loss and acne. It is also helpful in the healing of skin and reduction of scars.

Phytonutrients, polyphenols and antioxidants for protecting and nourishing skin

Most the colorful fruits and vegetables have phytonutrients in them of which polyphenols have antioxidant properties. They are found in a wide array of fruits and vegetables.
For example, most legumes; fruits such as apples, blackberries, blueberries, cantaloupe, pomegranate, cherries, cranberries, grapes, pears, plums, raspberries, aronia berries, and strawberries; and vegetables such as broccoli, cabbage, carrot, beet, celery, onion and parsley are rich in polyphenols. Many of these also contain antioxidant vitamins C and E.

Skin is continuously exposed to metabolic toxins from within and also exposed to exogenous sources of oxidative stress. Ultraviolet radiation from the sun is responsible for the extrinsic type of aging, sometimes termed photo-aging. The effects are thinning of the dermis, loss of moisture, loss of elasticity, appearance of wrinkles and dryness. These damages are due to free radials created by sun exposure as well as from metabolic processes. These free radicals damage cells and kill them. The antioxidants react with these free radicals by neutralizing them and protect us from cell damages.

What types of fruits and vegetables are to be consumed for nourishing skin?

Colorful red, orange, blue, purple and yellow fruits like oranges, kiwi, tangerines, strawberries, mangoes, apricots, plums, Blueberries, blackberries and red grapes and vegetables like tomatoes, carrots, sweet potatoes, winter squash, beets, purple cabbage, yellow and orange bell peppers have considerable amounts of nourishing alpha-carotene, beta-carotene, lycopene, zeaxanthin and lutein. Beta-carotene and lycopene are potent antioxidants protecting our skin from the damaging UV rays of the sun. Many of these also contain nourishing vitamin C.

Dark green and cruciferous vegetables contain Vitamin C, folate and zinc essential for nourishing our skin and also for protecting it from pimple flareups.

Fruits may be consumed as fresh, canned, frozen, or dried, and may be whole, cut-up, or pureed forms. Vegetables may be raw or cooked; fresh, frozen, canned, or dried/ dehydrated; and may be whole, cut-up, or mashed.

To sum up what we put inside our body for enhancing the glow and beauty of our skin is more important than what we apply on it. Food laden with sugars and fats overly taxes our digestive system as well as creates free radicals and toxins which cause blemishes, wrinkles and acne breakouts. On the other hand, fruits and vegetables are very essential components of food for protecting and nourishing our skin.
Interesting topics in dynamic skin care:
References:
1. http://www.choosemyplate.gov/
Image source: 
http://www.choosemyplate.gov/

Current topic:
Nourishing skin with fruits and vegetables.

Wednesday, October 24

Blisters on hands and feet - Small itchy water blisters - Dyshidrosis?

Small itchy water blisters - Blisters on hands and feet
Blisters on hands and feet can be due to dyshidrotic eczema, a skin condition, initially appearing as small itchy clusters of clear water (fluid-filled) vesicles. Usually this condition involves center of the palms and also sides of the fingers; but occasionally the soles of the feet may also get affected. The initial small, itchy bumps get filled with clear fluid to become water blisters, which may eventually break or burst while scratching them or using hand or feet. This may cause the skin to crust, crack and peel.

Typical symptoms of dyshidrosis blisters on hands and feet

  • These itchy blisters are small.
  • They may appear singly or in clusters.
  • They are deep-seated and are opaque.
  • Intense itching is usually present. In very rare cases there may be no itching.
  • These small blisters do not break easily.
  • Broken water blisters release colorless water like serum.
  • Skin in the broken vesicles crusts and cracks.
  • Lymph node swelling may be present during the outbreak.

Causes and effects of dyshidrotic eczema

Dyshidrosis also known as dyshidrotic eczema, vesicular eczema or pompholyx is more common is warm weather. These blisters tends to recur every two or three weeks and may become chronic on hands and feet. The exact cause of this idiopathic skin condition on hands and feet is not completely understood. Skin irritants appear to trigger this condition. These water blisters are not contagious and will not spread by touching of hands or feet. Its unsightly nature can lead to mental stress and social anxiety depression. Cracked and peeling skin can increase the risk of infections in the affected areas on hands and feet.

Triggering factors of small itchy water blisters on hands and feet.

  • Many triggering factors are associated with these small itchy water vesicles.
  • Genetic: In some cases this skin condition of small water vesicles is found to be passed down in families.
  • Stress: People under mental and physical stress have been found to develop these small itchy blisters.
  • Nickel: Frequent contacts with metals like chromium, nickel and cobalt, especially nickel have been found to give rise to these small itchy blisters in some people. Consuming canned products has caused these water vesicles in some individuals.
  • Chemicals: Contact with detergents, perfumes and other household chemicals has been found to trigger small water blisters in some people.
  • Allergies: Individuals prone allergies, urticaria and asthma are also prone to dyshidrotic eczema on hands and feet.

Treating dyshidrotic eczema blisters on hand

  • Scratching the affected itchy area must be avoided.
  • Topical steroids have been found to be effective in reducing the inflammation and itch. However their long-term use has to be avoided, considering their side effects.
  • Antihistamines are prescribed to reduce the itch and inflammation.
  • Dilute water solution of potassium permanganate (KMNO4) is useful in drying out the vesicles and controlling contact infections on hands and feet.
  • In some chronic cases of infected dyshidrotic eczema blisters, Dapsone (diaminodiphenyl-diphenyl sulfone), an antibacterial sulfonamide has been used successfully.
  • If the triggering factor is nickel, avoiding nickel rich foods like oatmeal and chocolate, avoiding canned food and avoidance of atmospheric exposure to nickel can help.
  • Persistent and worsening small itchy blisters on hands and feet must be evaluated by a healthcare professional for proper treatment.
Sudden appearance of tender feeling to touch can be a hint of progressive damage to the peripheral nerves or even the spinal cord and the brain.
Related topics of interest in skin care:
1. Cosmetic procedures with lasers.
2. Nevus simplex - Salmon patches.
3. What is hemangioma?
4. Skin hemangioma removal.
5. Carotene in carrots and orange skin.
6. Types of urticaria.
7. Chronic urticaria.

Image sources of small itchy water blisters on hands and feet: 1.http://en.wikipedia.org/wiki/File:Dyshidrosis.JPG
2.http://en.wikipedia.org/wiki/File:Dyshidrosis_sole.jpg
3. http://en.wikipedia.org/wiki/File:Palmar_dyshidrosis_peeling_stage.JPG

Current topic:
Dyshidrotic eczema (pompholyx) appear as small itchy water blisters on hands and feet.

Saturday, September 1

What are Salmon Patches? - Nevus simplex Birthmarks on Babies

Home > Reddened skin conditions > Salmon Patches - Nevus simplex birthmark on babies.
Salmon patches (nevus simplex) are very common vascular birthmarks found in about 30% of newborns.
These are congenital capillary malformations caused by dilated and stretched capillaries under the skin. Medically they are termed nevus simplex or n. flammeus nuchae. Salmon patches are also known as 'stork bite' when they occur at the nape of the neck and as 'angel's kiss' when they occur on the forehead, around eyes or between the eyebrows.

Salmon patches - Signs and symptoms

Nevus simplex is usually present at birth and in a few cases it may appear in the early weeks of life. Though these birthmarks may appear anywhere on the body, they are usually found on the back of the neck, forehead, on or around eyelids, on or around nose and upper lip.

Salmon patches - Diagnosis

Nevus simplex are easy to diagnose by visual observation. Salmon patches are pink in color and appear flat. They are irregularly shaped and may appear as small lesions or may cover a great area. During the flushing of the face due to change in temperature or crying of the baby these marks turn dark red. When pressure is applied on them, these birthmarks fade and appear pale.

Differential diagnosis of salmon patches

Nevus simplex can be differentiated from birthmarks like hemangiomas and port-wine stains. Skin hemangiomas have a rapid growth phase followed by an involution phase. They appear as raised swellings. Port-wine stains, may initially may have similar appearance, but do not fade and persist. Over time, port-wine stains become dark red or purple in color, thicken, become uneven and show hypertrophy (increased tissue mass). Nevus simplex are flat and do not grow.

Treatment of salmon patches

These birthmarks are temporary and in most of the cases they fade and disappear by two years. Normally nevus simplex do not require treatment as they disappear with the growth of the baby. If these birthmarks persist beyond three years, usually in the back of neck, they can be removed by cosmetic laser procedure to improve the aesthetic appearance of the baby.  There is no known preventive treatment for these birthmarks.

Prognosis
Most of these birthmarks fade and disappear in two years. Nevus simplex on the nape of the neck may not resolve and may persist. However salmon patches must be examined by pediatrician to rule out any complications or disorders.

Skin Care topics Of interest:
  1. Cosmetic laser treatments.
  2. Skin hemangioma treatments.
  3. What is a hemangioma birthmark?
  4. Carotene in carrots and orange skin discoloration.
  5. Types of urticaria (hives).
Current Skin Care topic: Salmon patches (nevus simplex) birthmarks on babies .

Skin hemangioma treatments - Hemangioma removal

Home > What is hemangioma? > Skin hemangioma - treatment and removal
Early removal of skin hemangioma with combination or multiple treatment options helps in reducing the risks of scars, cosmetic blemishes, facial disfigurement and other serious complications.
There are many treatment options available for removal of hemangioma on skin. Depending upon the need, individualized treatment plans can be opted for each patient as well as each lesion.

Medical observation and evaluation of hemangioma

     There is a drastic change from the traditional approach to hemangioma relief, like ‘leave it alone it will go away’, to having a close medical observation, frequent evaluation of the lesions and early intervention and removal, if necessary, to avoid future complications, life-risks and cosmetic skin disfigurements.

     Only about 2% of infantile skin hemangiomas are actually visible at birth. Tollefson M.M and Frieden I.J in their study "Early growth of infantile hemangiomas: what parents' photographs tell us." concluded that the precursors were present at birth in 65% of patients. They found that IH growth was nonlinear; most rapid growth occurred between 5.5 and 7.5 weeks of age and that the most rapid hemangioma growth occurred before 8 weeks of age. Megha M. Tollefson and colleagues found that the mean "optimal age for referral" was 4 weeks of age.

     They suggest "a need for a paradigm shift in the timing of referral and initiation of treatment of high-risk IH so that therapy can be initiated before or early in the course of most rapid growth, rather than after it is already completed".

Hemangioma treatment and removal with medications

     Steriods are the first-line medications for the treatment and removal of skin hemangiomas. As oral systemic corticosteroids slow down or stop the growth of lesions, they are successfully used for treatment and removal of rapidly proliferating lesions. By blocking the rapid proliferation phase, the involution phase may get advanced. This helps in buying time for taking up other treatment and removal strategies.

     Some infants may develop side effects for steroids like immunosuppression, gastrointestinal upset or retarded growth and hence close monitoring is necessary during the healing.

     Intra-lesional injections of corticosteroids into localized, small or deep skin hemangiomas in problematic areas like eye lids and ear canals have been found to be useful. Topical corticosteroids are useful in removal of small superficial strawberry birthmarks on skin.

     Propranolol, a sympatholytic non-selective beta blocker, has been used for many years in treatment of hypertension, anxiety and panic. In recent studies it was found that propranolol can be used for treatment of severe infantile hemangiomas. Further controlled trials have to be conducted for proving its efficacy for therapetic use. Many adverse drug reactions (ADRs) like  nausea, diarrhea, bronchospasm, hypotension, heart failure and dizziness are associated with the use of propranolol.

     Vincristine, a mitotic inhibitor used in cancer chemotherapy, has been successfully used for treatment and removal of lesions, which are problematic and are affecting vital functions. Vincristine is delivered via intravenous infusion. As vincristine has main side-effects like peripheral neuropathy, hyponatremia, ascending paralysis, and spinal nerve demyelination, it has to used with great caution.

     Interferon-alpha injections have been used successfully for treatment and removal of lesions affecting vital functions. Interferon-alpha also has many  adverse effects like flu-like symptoms, neutropenia, immunosuppression and convulsions.

Treatment and removal with surgical excision

     Hemangioma lesions are operable both during proliferation and involution phases. However the removal of proliferating skin hemangiomas by surgical excision is potentially risky due to possibility of hemorrhage and damage to vital tissues. This procedure has to be performed only by well trained surgeons. This type of early intervention and removal can preserve vital functions and reduce the psychosocial impacts associated with cosmetic disfigurement during childhood.

     Surgical excision and removal of loose skin or dilated bundles of blood vessels remaining after the involution of hemangioma is recommended to improve the esthetic appearance of the child. Generally lesions which regress slowly are likely to leave atrophic and hypertrophic scars, thinning of the skin or structural irregularities of the skin. Removal of these skin blemishes may require corrective surgery.

Skin hemangioma treatment and removal with lasers

     Among the various laser treatments available pulsed dye laser (PDL) with a dynamic cooling device is the first-line laser treatment for removal of these superficial skin lesions. Pulsed dye laser is very helpful in case of ulcerated skin lesions and telangiectasia (broken blood vessels) after regression.
   
     For removal of lesions involving deep hemangiomas of oral cavity, larynx, pharynx or airway, Nd:YAG laser can be used. Nd:YAG (neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12) is a crystal that is used as an active laser medium for solid-state lasers. Potassium titanyl phosphate (KTiOPO4) or KTP laser and carbon dioxide lasers are used for treatment and removal of airway hemangiomas.

Skin Care topics of interest:
1. What is hemangioma? What are the causes of hemangioma?
2. Carotene in carrots and orange skin discoloration.
3. Types of urticaria (hives).
4. Chronic idiopathic urticaria treatment.
5. Acute urticaria (hives).


Current Skin Care topic:
Skin hemangioma - treatment and removal.

References:
1. Tollefson MM, Frieden IJ. Early growth of infantile hemangiomas: what parents' photographs tell us. Pediatrics. 2012 Aug;130(2):e314-20. Epub 2012 Jul 23.
2. Haggstrom AN et al. (September 2006). Pediatrics 118 (3): 882–7. doi:10.1542/peds.2006-0413. PMID 16950977. "Prospective study of infantile hemangiomas: clinical characteristics predicting complications and treatment".

Sunday, August 19

What is a Hemangioma? What are the Causes of Hemangioma?

Home > Reddened skin > What is a Hemangioma? Causes of Hemangioma.
Hemangioma is a benign tumor formed by the abnormal growth and buildup of blood vessels. The cause of hemangioma is unknown.
Hemangioma usually appears on the skin, especially on the head, face and neck. It may form in the top skin layers (capillary) or deeper in the skin (cavernous). It may also appear on the internal organs like liver, spine and vertebrae. The term hemangioma comes from Greek words meaning "blood-vessel-tumor".

These lesions are the most common benign tumors in children. These lesions may be present at birth as birth marks having faint reddened areas or develop after birth in the early months. Usually these tumors grow rapidly for about twelve months. Then there is a resting phase with little change in appearance for another twelve months. Then the involution phase starts and causes the lesions to diminish in size and disappear in ten years. In rare cases it may persist beyond ten years.

Hemangiomas and vascular malformations

     Earlier the term hemangioma was used to denote a variety of vascular lesions of infancy and childhood. Mulliken JB. and Glowacki J. categorized these conditions into  hemangiomas and vascular malformations. Hemangiomas have a proliferating phase characterized by endothelial hyperplasia which causes rapid growth of tumor. Then there is an involution phase with histological fibrosis and fat deposition followed by a regression phase. Under the microscope, these lesions appear as aggregates of closely packed capillaries filled with blood having endothelial lining.

     Vascular malformations are usually seen at birth and they grow proportionately with the child-growth. Vascular malformations consist of abnormal arteries, veins and capillaries and are essentially permanent. This categorization helps in deciding on the type of treatment required, if any.

Causes of hemangioma

     The exact cause of this benign tumor is unknown. Several views and hypotheses have been suggested as possible causes of these lesions. Several studies suggested a role for the estrogen hormone for their development. A study suggested that higher levels of estrogen circulating in the infant blood coupled with the localized tissue hypoxia may be a cause or a triggering factor for these lesions.

     Another study hypothesized that embolisms of maternal placenta on to dermis of fetus may be the cause of hemangioma. However this view was contradicted by the DNA studies of the mother and lesion tissue. More research is required to know the cause of the explosive rate of growth of these tumors.

     Hemangioma is more prevalent in Caucasian infants than in Asian infants. It is rarely found in African-American infants. About 5% of Caucasian infants are born with these lesions. The cause of this ethnic variation is unknown. The low amount of melanocytes present in fairer skin may be a cause for the development of these tumors. Premature infants and small infants are more prone to have or develop these tumors. Further, when compared to males more number of female infants are affected.

     These tumors have potential for complications and permanent scarring. The risks involved include visual obstruction, breathing obstruction, ear canal obstruction facial disfigurement or bleeding ulceration. The tumors of the internal organs can lead to pain, impaired organ function or failure. When the tumor is very large it may create excess load and stress on the heart. The presence of lesions may have a psychological impact on the child and cause emotional distress and behavioral problems. Hence the presence of hemangioma in infants requires medical advice and early treatment.
Skin Care topics of interest:
1. Carrots carotene and orange skin.
2. Types of Urticaria (hives).
3. Treatment of chronic idiopathic urticaria.
4. Acute Urticaria (hives).
5. Types of albinism disorders - Causes and genetics

Current Skin Care topic:
What is a Hemangioma? Causes of Hemangioma.

References:
 1. Haggstrom AN et al. (September 2006). Pediatrics 118 (3): 882–7. doi:10.1542/peds.2006-0413. PMID 16950977. "Prospective study of infantile hemangiomas: clinical characteristics predicting complications and treatment".

Saturday, August 18

Carotene in carrots - Orange skin discoloration

Orange skin discoloration - Carotene in carrots
Excess consumption of carotene in carrots causes orange yellow skin discoloration. The β-carotene in carrots contributes to its orange color.
Though cosmetically displeasing to some, there is no apparent health impact of orange skin discoloration (carotenemia). However possible health effects of this condition have to be well researched.

Carotene in carrots

Carrots ((Daucus carota subsp. sativus) belong to Apiaceae family and are cultivated throughout the world. In a research study done in Netherlands it was found that regular consumption of carrots lowered the risk of cardiovascular disease (CVD). It was found to be due to the antioxidant activities of the carotenoids and polyacetylenes (falcarinol and falcarindiol) present in carrots.

Carotenes are a type carotenoids (tetraterpenoid organic pigments) which lack oxygen in their structure and are pure hydrocarbons. These fat-soluble carotenoids occur in the chloroplasts and chromoplasts of plants and occur in higher concentrations in some plants as in carrots giving them orange color.

Professor Heinrich Wilhelm Ferdinand Wackenroder (8 March 1798 – 4 September 1854), a German chemist and a professor at the University of Jena, isolated carotin (carotene) from carrots. Its structure was determined by Professor Paul Karrer (April 21, 1889 - June 18, 1971, a Nobel laureate, in early 1930s. Alpha-carotene present in carrots is found to be protective against the proliferation of human cancer cells.

β-carotene (C40H56) is the most studied of about fifty carotenoids identified in the human diet. Carrots are high in the (all-E)-beta-carotene isomer. It is an isomer form having higher bioavailability, provitamin A activity, and antioxidant activity when compared to Z (cis) isomer form of this carotenoid. The levels of all three Z isomers in raw carrots are low and are about 1.8% of the total isomers. Storage at low temperatures in fact increases the (all-E)-beta isomers.

There is thermal isomerization during cooking of carrots causing generation of all the three Z isomers. To get the maximum benefits, carrots should be stored at low temperatures. Carrots should be consumed raw or boiled for less than fifteen minutes to limit Z isomerization.

β-Carotene in fruits and vegetables

The β-carotene in many fruits and vegetables contributes to orange color. Orange and yellow fruits like mangoes, cantaloupe and papayas and orange roots like yam and carrots are rich sources of this carotenoid.

Though the Vietnamese gac fruit (Momordica cochinchinensis) and crude palm oil contain the highest amount of β-carotene, nearly ten times higher than carrots, gac fruit is less known outside Southeast Asia and the crude palm oil loses the β-carotene while processing and refining.

Carrots and yellow/orange skin discoloration

Excessive consumption of fruits and vegetables containing β-carotene causes carotenosis (carotenodermia, carotenemia or hypercarotenemia), a harmless condition giving a yellow-orange tint to the epidermis. This is due to deposition of these carotenoids in the outermost epidermal layer of skin.

This yellow-orange discoloration differs from that caused by the jaundice disease. In jaundice apart from yellowish pigmentation of the epidermis, the conjunctival membranes over the sclerae (whites of the eyes) also turn yellow whereas in carotenodermia sclerae remain white.

Carotenes have vitamin A activity and get partially converted into vitamin A (retinol) within the intestinal mucosa by a dioxygenase enzyme. If the vitamin A status of the individual is high, the conversion decreases and the excess carotenoids are stored/deposited in the fat tissues and epidermal layers. These carotenoids are deposited in the intercellular lipids of the stratum corneum of the skin.

Though the orange coloration can be generalised, it is more prominent in areas where stratum corneum is thicker and also in areas where there is profuse sweating. Palms, soles, nasolabial folds and behind ears are more prone to discoloration. The orange discoloration of epidermis reverses on cessation of consumption of carrots and other foods containing this carotenoid.

Some underlying health disorders may cause secondary carotenemia wherein increased serum lipids and decreased metabolism of carotenoids are the causes. In such cases treating the disease condition will resolve carotenemia.

If the orange skin discoloration is due to excess consumption of carrots, fruits or other vegetables, cessation of excess intake will reverse the skin condition without any blemishes, spots and marks.


Related topics:

Popular topics:

References:
1.Imsic M, Winkler S, Tomkins B, Jones R. Effect of storage and cooking on beta-carotene isomers in carrots ( Daucus carota L. cv. 'Stefano'). J Agric Food Chem. 2010 Apr 28;58(8):5109-13.
Current Natural Skin Care topic: Carrots - Carotene - Orange skin discoloration

Sunday, August 5

Chronic idiopathic urticaria (hives) treatment

Chronic idiopathic urticaria treatment
Treatment of chronic or idiopathic urticaria involves use of antihistamine medications and avoidance of triggers or aggravating factors.
In the treatment of chronic idiopathic urticaria the principle approach is to control mast cells by suppressing IgE stimulation and/or the histamine release. Mast cells release three major types of histamines, H1, H2 and H3. As the skin contains both H1 and H2 histamine receptors, use of H1 and H2 antihistamines is usually considered for chronic idiopathic urticaria treatment.

Oral antihistamines for treatment of chronic idiopathic urticaria

     Oral antihistamines have been the first line treatment for all patients with chronic or idiopathic urticaria. Non-sedating 2nd generation H1 antihistamines are used with good treatment response. When itching is intense, especially in the night, sedative first generation H1 antihistamines are given in the night and non-sedating 2nd generation H1 antihistamines are given during the day for the idiopathic urticaria patient. Increasing the dosage up to four fold is recommended if the response to the initial dosage is found inadequate during chronic idiopathic urticaria treatment.

First generation H1 antihistamines for chronic or idiopathic urticaria
Chlorpheniramine, hydroxyzine, and diphenhydramine are the first generation H1 antihistamines having side effect of sedation. Though these antihistamines have proven record of efficacy in urticaria treatment, with the advent of second generation drugs their sedative effects appear as a big drawback in the treatment of chronic idiopathic urticaria.

Non–sedating 2nd generation H1 antihistamines in urticaria treatment
Loratadine, fexofenadine, cetirizine, levocetirizine, terfenadine, desloratadine and mizolastine are non sedating second generation H1 antihistamines very much in use in the treatment of chronic idiopathic urticaria.

Nonsedating H2 antihistamines for chronic idiopathic urticaria
Cimetidine, ranitidine, famotidine and nizatadine are H2 antihistamines having no sedating side effect. These drugs have been used successfully along with H1 drugs for the treatment of chronic or idiopathic urticaria.

Treatment of antihistamine –resistant chronic idiopathic urticaria

Some forms of chronic idiopathic urticaria do not respond well to antihistamine treatment. In some patients chronic idiopathic urticaria may become antihistamine -resistant. In such instances non antihistamine medications like systemic corticosteroids, leukotriene modifiers or immunosuppressants may be considered during urticaria treatment. However their use has many limitations due to their side effects.

Role for systemic corticosteroids
Systemic glucocorticoids like prednisone have been used for lessening swelling, inflammation and itch in chronic idiopathic urticaria. However they can be used only for a short treatment periods as they have serious side effects like Cushing syndrome, skin damage, increased blood glucose levels, sleep disturbances, weight gain and psychological effects. Corticosteroids can weaken the immune system and worsen the existing infections of patients with idiopathic urticaria.

Leukotriene modifiers for chronic idiopathic urticaria
     Asthma medications like montelukast and zafirlukast are  leukotriene receptor antagonists (LTRA). They have been found to be effective in the treatment of chronic idiopathic urticaria when used along with non–sedating 2nd generation H1 antihistamines like loratadine. Side effects of leukotriene modifiers include gastrointestinal disturbances, headaches, general hypersensitivity, insomnia, sleep disorders, aggression, anxiousness, hallucinations, depression, irritability, and increased bleeding tendency.

Immunosuppressant drugs
Immunosuppressant drugs like cyclosporine and cyclosporin G are useful in the treatment especially of chronic autoimmune urticaria. As immunosuppressants they suppress the activity of the immunological system by obstructing the activity and growth of T cells. Treatment with immunosuppressants may be associated with a number of potentially serious adverse drug reactions (ADRs) like gastrointestinal disturbances, peptic ulcers, pancreatitis, convulsions, kidney and liver dysfunction, increased vulnerability to opportunistic infections and flare-up of current infections. Ciclosporin is listed as IARC Group 1 carcinogens as sufficient evidence of carcinogenicity in humans has been established.

Maintenance treatment
Once the symptoms resolve the treatment must be continued and tapered off after three months. The dosage of the medication is gradually reduced every two weeks. In many cases relapse has occurred when the medication is withdrawn soon after the resolution of symptoms.

Topical agents
Certain topical agents like calamine lotion, menthol with aqueous cream, and crotamiton lotion have been found to soothe the inflammation and itching. Applying cold compress or ice to the affected area for about 15 minutes relieves swelling, itching and pain. This may be followed up with application of calamine lotion.

Considerations for children
There are specific approvals and restrictions by FDA for use of various antihistamine medications in children considering their age. Please check the drug information provided by the manufacturer for use in children before usage.

Considerations for pregnant women
First-generation antihistamine such as chlorpheniramine is the safest choice for treatment of chronic idiopathic urticaria in pregnant women. Considerable usage experience is gained in its long term use without any fetal harm.
For drugs like cetirizine and loratadine there are no  controlled data in human pregnancy and have been assigned to pregnancy category B by the FDA. These drugs are recommended for use during pregnancy when need benefit outweighs risk. They are excreted into human milk. Hence their use is not recommended in nursing mothers.
Like cetrizine, montelukast and zafirlukast have been assigned to pregnancy category B by the FDA.
Cyclosporine and prednisone have been assigned to pregnancy category C by the FDA and are potentially harmful to fetus.

Avoidance of triggers or exacerbating factors

In some cases of chronic urticaria the triggers are identifiable. In such cases avoiding the trigger itself is the treatment. However in idiopathic urticaria the causes are not known. Avoiding the possible causes may bring relief to the patient affected by the idiopathic allergy.
  • Avoid tight fitting clothes, shoes and belts.
  • Try to keep your surroundings cool.
  • Avoid hot or cold baths.
  • Avoid stress and tension.
  • Do not do strenuous exercise.
  • Inform the doctor about your proneness to urticaria when he prescribes medications.
  • Avoid possible food triggers.
  • Avoid exposure to sun.
  • Avoid exposure to cold winds.
  • Avoid exposure to germicides, pesticides and detergents.
Avoiding the triggers and proper and complete treatment will help in resolving chronic idiopathic urticaria without any skin scars, blemishes or discolorations.
Advertisements


Topic of interest:
Types of urticaria - Types of physical urticaria

Reference:
1. Kaplan AP, Greaves M. Pathogenesis of chronic urticaria. Clin Exp Allergy. 2009 Jun;39(6):777-87. Epub 2009 Apr 22.

Thursday, August 2

Types of urticaria (hives) - Types of physical urticaria

Home > Types of urticaria - Types of physical urticaria
Classification of urticaria types into acute and chronic are accepted worldwide. Arbitrarily, the urticaria lasting less than six weeks is called acute type whereas the one lasting longer than six weeks is considered chronic.
Further, if psychosomatic and physical influences trigger this condition it is called physical urticaria. The conditions are called idiopathic when the causes are not known. Nearly 50% of the occurrences are caused by unknown factors.

Physical urticaria

    These types are very distinct and are induced by exogenous physical stimulus. The source of stimulus can be thermal, mechanical and cholinergic. Ten percent of chronic urticaria are physical urticaria. Considering the types of stimuli, these typs are categorized into sub-groups like dermatographism, delayed-pressure, cholinergic, cold, solar, heat, aquagenic and vibratory urticaria.

    Dermatographism is very common and induced by scratching or firmly stroking the skin. The swollen skin spots may appear immediately and resolve in about 30 minutes. In a normal healthy person though scratching may produce linear reddening without itching, in dermographism, itchy swelling develops. If the skin swelling persists or causes discomfort, taking antihistamines may resolve them.

    Cholinergic or stress type is widespread  and is caused due to rise in the core body temperature. Strenuous exercise and warm or hot bath may trigger the condition. Numerous small welts appear causing itching, tingling and burning sensation. The red spots appear quickly and last up to two hours. It is considered that psychosomatic influences stimulate parasympathetic nervous system leading to release of histamine throughout the body.

    Cold influenced physical urticaria is common in youngsters. On exposure to cold winds, cold water and cold climate, red spots appear on exposed parts like face, neck and hands. There is another hereditary type which may cause red swollen spots all over the body, nine to eighteen hours  after exposure. For persons with this condition, there is a grave danger in swimming in cold waters, as there may be massive release of histamine leading to low blood pressure and shock.

    Delayed-pressure urticaria is a rare physical type and skin swelling occurs in the areas where there is sustained pressure. Usually in this delayed type, swollen spots appear approximately six hours from initial stimulus and may last between eight hours to three days. Belts, straps, tight-fitted clothing and activities giving sustained pressure on the skin can trigger this condition.

    Heat induced urticaria is a rare physical type wherein swollen spots appear on continued application of heat. The spots may appear within two to three minutes of exposure and may last up to one hour.

    Solar or sun induced urticaria is caused on exposure to sun on the exposed skin areas. Though this physical type appears within a few minutes of exposure, it resolves within a few hours from withdrawing the sun exposure. Depending upon the wavelength of light triggering the condition, six different types are known.

    Water (aquagenic) urticaria is triggered on contact with water and the response is not temperature dependent. The skin swelling appears within one to ten minutes after the contact and may last up to two hours. Histamine release is not involved in this condition and there is a opinion that sensitivity of skin to additives in the water may the triggering factor.

    Vibratory urticaria is a rare physical type and develops on contact with vibration. Painful angioedema develops within five minutes after contact with vibration and may last up to one hour.

    Exercise-induced anaphylaxis is a rare physical type causing skin swelling and itchiness, shortage of breath and low blood pressure. The symptoms may appear within thirty minutes from the start of exercise and sometimes may prove fatal. Unlike cholinergic Urticaria, in this type hot bath does not trigger the condition. Hospitalization and treatment with antihistamines, epinephrine and ventilator support may be required.

Drug-induced type of urticaria

    Many drugs have been found to cause allergic reactions like minor skin rashes and urticaria. The most common causes of drug induced allergy are penicillin and related antibiotics like amoxicillin and ampicillin. Other common urticaria inducing drugs are sulfonamides, antiepileptic drugs, antidiabetic drugs, insulin preparations, aspirin, dextroamphetamine and clotrimazole. Some of them can lead to severe physical symptoms like angioedema, severe asthma, anaphylaxis and cardio-respiratory failure.

    Knowing and avoiding the triggering factors and use of appropriate antihistamine medicines can resolve all types of physical urticaria without leaving any skin blemishes, discolorations and scars.

Related topic of interest:
Acute urticaria
Image:
James Heilman, MD, http://commons.wikimedia.org/wiki/User:Jmh649/CC BY-SA 3.0

References:
1.Marcus Maurer and Jürgen Grabbe, Urticaria: Its History-Based Diagnosis and Etiologically Oriented Treatment, Dtsch Arztebl Int. 2008 June; 105(25): 458–466. PMCID: PMC2696901
2.Barbaud A, [Physical urticaria], Ann Dermatol Venereol. 2003 May;130 Spec No 1:1S16-27, PMID: 12843805