What is tinea versicolor?
Tinea versicolor is a type of fungal skin infection that is visible as patches of discolored skin on neck, upper arms, chest and back. It is commonly known as a fungus on the body and should be differentiated from fungual infections on the groin, feet, scalp and other regions. The majority of infected people are either teenagers or young adults. In the United States, around 2% to 8% of the population is thought to have this infection. However, as much as 50% of the population can be affectedin hot and humid regions.
The name “tinea versicolor” is a misnomer. A variety of fungi can cause infections, including dermatophytes, yeasts and molds. Fungal infections of the skin are mostly caused by a class of fungi known as dermatophytes. Dermatophyte infections are commonly referred to as tinea (such as, tinea cruris or tinea pedis), which means ringworm. The name “tinea versicolor” suggests that the infection is due to a dermatophyte. However, tinea versicolor is actually a yeast infection, and its correct name is pityriasis versicolor. Despite this, the erroneous name has stuck because most people continue to use it.
Read more about ringworm on the skin.
Tinea versicolor affects only the superficial layers of the skin, and does not cause any physical pain to the infected person. Also, the infection is not contagious. However, it is a cause for considerable emotional distress due to the cosmetic disfiguration of the skin. The good news is that the infection is treatable. However, it takes several weeks to months for the skin to regain its natural color. After successful treatment, it can also recur, especially in warm and humid weather.
What are the symptoms of tinea versicolor?
The term “pityriasis” means “scales”, and the term “versicolor” means “multicolored”. This name appropriately describes the main feature of this infection, which is an appearance of round or oval lesions of multicolored (various shades of pink and brown) dry skin, especially on the trunk and the shoulders. In people with dark skin, the infected skin patches may appear lighter in color than the surrounding skin, because the fungus interferes with normal skin pigmentation. This appearance may be mistaken for vitiligo.
These patches of infected skin are first visible as small dots on the skin. They grow slowly and may eventually coalesce to form larger patches of discolored skin. Exposure to sun may aggravate the condition. However, it is important to note that the sun exposure does not cause the infection. Unlike dermatophyte infections, tinea versicolor infection does not spread to the most sun-exposed regions like the face and the forearms.
The discolored skin patches may be mildly itchy in some cases. The affected skin may also become scaly. Sometimes, tinea versicolor may present with atypical signs, which can lead to confusion in diagnosis. The patches may appear on areas such as face, elbows and abdomen. However, these are rare occurrences that are more likely to be present in people with an abnormally weak immune system.
What are the causes of tinea versicolor?
Tinea versicolor is caused by a particular type of yeast known as Malassezia (previously known as Pityrosporum). Malassezia furfur and Malassezia globosa are two subtypes of Malassezia that are mainly responsible for most cases of tinea versicolor. However, these yeasts are natively present on healthy skin and do not normally cause disease.
The yeasts on the skin normally exist in both active and inactive forms. The inactive forms are known as spores, and can be thought of as seeds. The active forms of the yeast are filamentous (also known as saprophyte). These grow out of the spores and feed on the dead skin. The growth of yeasts on the skin are normally kept in check by our body’s defense mechanisms (e.g., integrity of our skin and activities of our immune system) and the presence of other competing microbes on the skin. However, under some conditions, these growth checks are removed, the spores germinate into filamentous forms, and the yeasts start overgrowing on the skin.
Some of these growth-permissive conditions include:
- Hot and humid weather.
- Excessively oily skin.
- Hormonal changes in the body.
- A weak immune system
The overgrowth of the active forms of these yeasts are then visible as discolored patches (rashes) on the skin.
The exact causes of overgrowth of these yeasts on the skin are not completely understood. However, certain conditions predispose an individual to getting tinea versicolor. These include:
- Heat and humidity.
- Impaired immunity.
- Excessive sweating.
- Poor nutrition.
- Oily skin.
- Hormonal changes.
- Cushing’s disease.
What is the treatment for tinea versicolor?
The main line of treatment for tinea versicolor is anti-fungal medication. Anti-fungal medications could be applied directly to the affected skin regions (topical medication), or taken orally (systemic medication). In case of mild tinea versicolor infection, over-the-counter topical antifungal agents can be used.
Topical medications come in the form of creams, lotions, ointments and solutions. Some of the topical medications for tinea versicolor include:
- Selenium sulfide
- Ciclopirox olamine
- Sodium thiosulfate
Oral anti-fungal medications are given in the form of tablets or capsules. Some of the common oral medications include:
Oral anti-fungal medications are used when the spread of infection is too vast for effective treatment with topical application of anti-fungal creams. These are more effective in warding off tinea versicolor than the topical medications. Treatment with anti-fungal medication usually continues for about a month. However, it may take a couple of months (or more) before the skin color returns to its normal hue. During this period, it will help to protect the skin from direct sunlight and other sources of UV light.
How can tinea versicolor be prevented?
Despite successful treatment with anti-fungal medications, tinea versicolor can return. This especially occurs if the conditions for fungal overgrowth (like with hot and humid weather or weak immunity) are still present. In case there is a chance of recurrence, your physician may advise you to use some topical or oral medications once or twice a month (particularly during hot and humid months). Some of these preventive medications include:
- Oral: itraconazole, fluconazole
- Topical: selenium sulfide containing shampoo or lotion, ketoconazole
Image sourced from Dermatology Atlas (atlasdermatologico.com.br)