Pityriasis versicolor

Sophie Matzik is a freelance writer for the medical team.

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Pityriasis versicolor (bran fungus) is a fungal disease of the superficial layers of the skin. It is characterized by blotchy skin changes, especially on the back and chest. A yeast that is part of the natural skin flora triggers pityriasis versicolor. Therapy and course of the disease depend on the extent of the infection and individual health factors. Read everything you need to know about pityriasis versicolor here!

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. B36

Pityriasis versicolor: description

Pityriasis versicolor (also known as bran fungus) is a harmless fungal disease of the skin that only affects the upper layers of the skin. It is triggered by certain yeasts of the genus Malassezia. They are part of the natural skin flora and in healthy people settle in the hair follicles and on neighboring areas of the skin, especially on the head. When they multiply and spread vigorously, an outbreak of disease occurs. Factors such as profuse sweating can promote this.

In contrast to other fungal diseases, pityriasis versicolor is not contagious - not even in direct contact with the sick.

Pityriasis versicolor is the most common superficial fungal infection in the world. Adolescents from puberty and adults are particularly affected. In Germany, pityriasis versicolor is found in one to four percent of the population, in tropical regions between 30 and 40 percent. The risk of relapse is very high, especially in people who have certain risk factors for fungal diseases.

Pityriasis versicolor: symptoms

When Malassezia mushrooms multiply in Pityriasis versicolor, they form dense carpets of mushrooms on the skin: They initially appear as lenticular to penny-sized, round, sharply defined spots, the color of which is clearly different from normal skin color. These spots can melt together and form irregularly shaped, large-area discoloration. The color of the discoloration ranges from whitish to reddish-brown. Basically, there are light spots on dark skin and dark spots on light skin. This color variance is illustrated by the term "versicolor" (multi-colored) and comes about as follows:

The mushroom carpet does not allow the sun's rays (UV light) to penetrate the underlying skin, which prevents the formation of the skin pigment melanin there. In addition, toxins from the fungus inhibit melanin synthesis in the skin. This creates light spots (hypopigmentation) on dark or tanned skin. This form of bran fungus is called pityriasis versicolor alba.
On light skin, on the other hand, the fungus can lead to reddish-brownish skin lesions due to the formation of its own pigments (hyperpigmentation). Then one speaks of pityriasis versicolor rubra.

Fine, bran-shaped flakes of skin can peel off the affected areas. The German term for the disease "bran fungus lichen" refers to them.

The skin spots of the bran fungus occur mainly on areas of the skin rich in sebum glands on the trunk of the body, i.e. mostly on the chest and back. Other areas such as shoulders, arms and neck can also be affected. Sometimes there is a slight itchiness.

In rare cases, the skin infestation with Malassezia fungi leads to an inflammation of the hair follicles (Malassezia folliculitis). People with immunodeficiency are most likely to be affected by this (either through medication or with HIV infection).

Pityriasis versicolor: causes and risk factors

Pityriasis versicolor is caused primarily by certain yeasts Malassezia furfur, Malassezia globosa and Malassezia sympodialis. These fungi occur to a certain extent in all healthy people and, together with other microorganisms, form the normal skin flora.

Bran fungal outbreak occurs when the fungi suddenly multiply unchecked and spread across the skin. So far, it is not known what the impetus is. However, we know some risk factors that can promote the outbreak of a bran fungus. This includes a warm, humid environment in which the mushrooms can multiply well. Therefore, Pityriasis versicolor is widespread in tropical countries.

Heavy sweating (hyperhidrosis) and increased sebum production in the skin (seborrhea) also promote fungal growth. Other risk factors for pityriasis versicolor include, for example, the frequent use of fatty creams and a weakened immune system - for example due to medication or underlying diseases such as HIV.

In patients with underlying diseases and long-term therapy with glucocorticoids, antibiotics or immunosuppressants, the Malassezia fungi can also cause hair folliculitis. Small, reddened pustules emanating from hair follicles then develop on the chest, upper back, face, shoulder and neck area, which can be very itchy.

Pityriasis versicolor: examinations and diagnosis

The right contact person for any type of skin change is the dermatologist (dermatologist). In an initial conversation, he will collect your medical history (anamnesis). You have the opportunity to describe your complaints in detail. This can help the doctor make a suspected diagnosis. In order to rule out certain causes for the existing symptoms and to be able to narrow down the type of illness further, the doctor also asks questions such as:

Have you been on vacation lately and if so, where?
Are there any known skin diseases in your family?
Have you ever had skin changes like this before?

The medical history is followed by a physical exam. The doctor examines the skin changes and strokes them with a spatula. The bran-like scales that are typical of pityriasis versicolor can peel off.

In order to be able to determine the cause of the skin changes, the microscope helps: the doctor scrapes a sample of affected skin areas for assessment or he sticks a piece of scotch tape on the skin patches, presses it on firmly, then tears it off, stains it and places it under the microscope: In Pityriasis versicolor there are piles of rounded spores of Malassezia mushrooms and short fungal threads. The whole thing is reminiscent of "spaghetti and meatballs".

In addition, the doctor can examine the skin changes with a special light, the so-called Wood light. Areas of the skin on which there are fungi fluoresce yellowish-green.

Pityriasis versicolor: treatment

Pityriasis versicolor is not dangerous and is therefore less of a medical problem than of a cosmetic (aesthetic) problem.

The treatment is carried out with antifungal agents (antimycotics), whereby a local application (as a cream, shampoo) is usually sufficient. For example, there are creams with the active ingredient ketoconazole that are applied twice a day over a period of two weeks. In addition, doctors recommend the use of a shampoo containing active ingredients - in order to ensure the success of the therapy and prevent relapses, the head must always be treated even if the infection is low (the pathogen reservoir is in the scalp!).

In very pronounced cases of illness, if the local antimycotics are unsuccessful, a one-week systemic bran fungus treatment can be carried out: For example, tablets with itraconazole or fluconazole are prescribed.

Pregnant and breastfeeding women, as well as people with liver or kidney problems, should not take antifungal tablets.

After successful treatment of pityriasis versicolor, relapses occur very frequently, especially if the patient is appropriately prepared.

Pityriasis versicolor: disease course and prognosis

Pityriasis versicolor is generally good to treat. However, it can take a few months for the whitish patches of skin to become pigmented again.

Note the high risk of relapse with bran fungus. Patients are therefore often advised to regularly use shampoos containing antifungal agents as a preventive measure. Other tips for prevention:

Wear clothing that is as breathable as possible, especially in summer, which absorbs sweat from the skin or transports it to the outside (items of clothing made of synthetic fibers cannot absorb sweat well and also promote heat build-up under clothing)
showering or bathing frequently with the use of syndets (artificial washing substances that are gentle on the skin)
Always dry yourself well after showering or bathing

These measures are also advisable if there is an existing infection with Pityriasis versicolor.

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