Pityriasis versicolor (fungal lichen)

Pityriasis versicolor is a fungal disease of the skin. The disease is usually harmless and free of symptoms, but the fungal infestation can be perceived as cosmetically disturbing.

It is caused by the yeast Malassezia furfur (old name: Pityrosporum ovale), a fungus that occurs naturally on the skin and does not normally cause any symptoms. In some cases, however, the fungus changes shape and begins to enlarge abnormally, creating a skin condition that is harmless to health but disturbing cosmetically. The yeast Malassezia furfur also plays a role in the development of dandruff and cradle cap.

The Kleienpilz lichen mainly affects men. Favouring development factors are heavy sweating and a humid and warm skin climate. The infection is not contagious.

Lupus is caused by the fungus Malassezia furfur, which occurs naturally on the skin. The mechanism by which some people suddenly experience an excessive proliferation and thus the development of a Kleienpilzchte is as yet unexplained.

The following factors favour the development:

• Warm and humid climate on the skin surface
• Overweight
• Strong sebum production of the skin glands
• A weakened immune system, for example after years of cortisone treatment.

The Kleienpilzflechte is especially in tropical and subtropical areas quite common. In Europe, the number of cases increases especially in the summer months.

The visible skin changes in a disease develop over months. Complaints such as itching usually do not occur. Characteristic are the scaly, sharply defined round or oval patches, which sometimes merge and thus form large, map-like areas. In people with fair skin colour, the patches appear pale reddish to brownish, while darker skin shows white patches.

The areas around the neck, shoulders, back and chest are usually affected. In rare cases, areas of skin below the belly button may also be affected.

The hair roots on the chest and the back can also become infected by the fungus, causing an acne-like clinical picture (called Pityrosporum folliculitis). This primarily affects people with a weak immune system.

Since there are numerous skin diseases that cause a similar clinical picture as the Kleienpilzflechte, but require a different treatment, a reliable diagnosis by means of a microscope is necessary. For this purpose, skin scales are taken from the affected areas, treated with potassium hydroxide solution or a fluorescent dye (to make the fungal infestation more visible) and then examined under the microscope. The fungus Malassezia furfur appears enlarged in the form of hyphae (threads) and spores (round cells).

Another possibility is to use a skin sample to cultivate and multiply the fungi on a nutrient medium, as the exact fungal species can then be determined more easily due to the high number of fungal components.

A Kleienpilzflechte is usually treated externally with a special shampoo. These shampoos are available at pharmacies and contain antimycotics (antifungal agents) such as ketoconazole or miconazole. The affected skin areas are generously rubbed with it and after a certain exposure time, the shampoo can be rinsed off again. An internal application of antimycotics is normally not necessary in the case of Kleienpilzflechte.

If infection of the hair roots occurs, causing the appearance of pityrosporum folliculitis, it may sometimes be necessary to take ketoconazole or itraconazole capsules.

To aid in healing, the skin should be washed frequently with soap-free washing syndets with a skin-neutral pH. In addition, synthetic clothing should be avoided as it usually wicks away sweat more poorly than clothing made of natural fibres (e.g. cotton) and thus favours the fungal growth due to the humid and warm skin climate.

Even after a successful treatment, there is a high risk that a Kleienpilz lichen will form again over time. Shampoos containing selenium sulfide or ketoconazole can be used as a preventive measure.

With the help of antimycotics, the fungal disease can usually be treated quickly and effectively. However, the white skin patches persist for several months and only disappear when the epidermis has regenerated and the skin damaged by the fungus has been completely shed.

If the disease has already occurred, regular application of antifungal shampoos can prevent a later recurrence of the Kleienpilzflechte. The risk of a first disease can be reduced by avoiding disease-promoting factors such as overweight and a humid skin climate.