Tinea versicolor or pityriasis versicolor are fungal skin infections caused by fungi of the yeast variety of Malassezia group.
Overview and description of tinea versicolorTinea (pityriasis) versicolor fungal infections are usually superficial, benign, common, recurrent and not contagious affecting the stratum corneum layer of the epidermis. They are characterised by macules (color patches) which may be hyperpigmented (darker) or hypopigmented (lighter) appearing in multi colors of white, creamy, pale pink and brown. These spots of fungal infections are usually found on the upper arms, back, neck and upper chest. These fungus patches may have fine scales and itching (pruritus) may be occasionally present.
Fungi Malassezia furfur and M. globosa cause tinea versicolor fungal infectionsTinea versicolor (sun fungus) is caused by Malassezia group of fungi which are residents of human skin. They are part of the normal flora of the human skin. Recent studies have revealed that Malassezia globosa and M. furfur cause most of the tinea versicolor fungal skin infections. Though this skin fungus is present normally on the skin, under certain situations it starts to grow, proliferate and cause these infections.
Warm and humid conditions appear to be conducive for this tinea fungus to turn into pityriasis versicolor skin infections. These fungi are lipophilic and oily skin provides the right environment for their multiplication. Further it appears to affect the teenagers and young adults. May be it is due to hyperactivity of sebaceous glands in these age groups. Young children and elderly people are least affected by the tinea (pityriasis) versicolour fungal infections. Depending on the affliction, there are many types of these fungal infections.
Tinea versicolor type 1These fungi which are normally in the form of round or oval spores, when triggered put out slender filaments called hyphae and grow initially as small colonies. These colonies grow and overlap to form larger patches. There may be opportunistic infections and skin lesions present. The fungus produce azelaic acid which has skin bleaching properties, causing the white patches and the apparent symptom of this disease.
These areas do not tan and stand out as white or pale pink patches when the healthier skin gets tanned. In the basal layers of epidermis melanocytes produce melanin pigment clumps called melanosomes. In some persons the fungi can induce the melanosomes (brown pigments) to become bigger in size and give rise to hyperpigmentation and dark brown patches of tinea (pityriasis) versicolor.
Tinea versicolor type 2In this type of infection apart from the usual areas of affliction, the disease may affect face, fore head, arm pits, groins and extremities. This tinea (pityriasis) versicolor type is generally found in persons with weakened immune system.
Tinea versicolor type 3In this type fungal infections may involve the hair follicles on chest, back and hands.
Tinea versicolor type 4In this fungal form, about 3mm size, several, firm, reddish brown, monomorphic, inflammatory and itchy papules are formed.
Universal incidence of tinea (pityriasis) versicolor fungal skin infectionsThough tinea (pityriasis) versicolor causing fungi are present in nearly all adults, the fungal disease condition is experienced in relevance to temperature, moisture and age group. Humidity and heat play an important role in the development of these fungi. In America about 10% people develop tinea (pityriasis) versicolor, whereas in some tropical countries nearly 50% of the population get these fungal skin infections.
In countries like Sweden only 1% of the population develop tinea (pityriasis) versicolor. In temperate regions the tinea (pityriasis) versicolor sets in warmer summer months, fading with the onset of winter. In tropical regions this fungal disease persists and becomes chronic. Though it may affect any age group, often teenagers and young adults are the most affected by this fungal disease.
Tinea (pityriasis) versicolor is not specific to any gender or race. Tinea (pityriasis) versicolor fungal skin infections may recur after treatments. In most people though the disease may go away after treatment the restoration of the normal skin appearance takes several months. Tinea (pityriasis) versicolor fungal skin infections though have little or no physiological impact on the populations, they leave a psychological impact on the individuals with blemishes on the skin.