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Pityriasis versicolor (bran rash)

by Josephine Andrews
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Pityriasis versicolor (bran rash) is a fungal disease of the superficial layers of the skin. It is characterized by patchy skin changes, especially on the back and chest. A yeast that is part of the natural skin flora is the trigger of pityriasis versicolor. Therapy and the 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 valid 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 is a harmless fungalskin disease that only affects the upper layers of the skin. They are triggered by certain yeast fungi of the genus Malassezia . They are part of the natural skin flora and settle in healthy people in the hair follicles and adjacent skin areas, especially on the head. When they proliferate and spread, the disease breaks out. Factors such as heavy sweating can favor this.

In contrast to other fungal diseases, pityriasis versicolor is not contagious – not even through direct contact with sick people.

Pityriasis versicolor is the most common superficial fungal infection worldwide . 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 in 30 to 40 percent. The risk of recurrence is very high, especially in people who have certain risk factors for fungal diseases.

Pityriasis versicolor: symptoms

Due to strong proliferation, Malassezia fungi form dense fungal carpets on the skin in pityriasis versicolor: They first appear as lentil to penny-sized, round, sharply defined spots , the color of which differs significantly from the normal color of the skin. These patches can fuse together to form irregularly shaped, widespread discolorations . The color of the discoloration ranges from whitish to reddish-brown. Basically, light spots are found on dark skin and dark spots on light skin. This color variance is illustrated by the term “versicolor” (multicolored) and comes about as follows:

  • The carpet of fungi does not allow the sun’s rays ( UV light ) to penetrate the skin underneath, which means that the formation of the skin pigment melanin does not occur there. In addition, toxins from the fungus inhibit melanin synthesis in the skin. This is how light spots (hypopigmentation) appear on dark or tanned skin. This form of bran lichen is called pityriasis versicolor alba .
  • On light skin, on the other hand, the fungus can lead to reddish-brown skin lesions (hyperpigmentation) through the formation of its own pigments. Then one speaks of pityriasis versicolor rubra .

Fine, bran-shaped skin flakes can detach from the affected areas . The German name of the disease “bran fungus lichen” refers to them.

The skin patches of bran lichen occur mainly on skin areas rich in sebaceous glands on the trunk of the body, ie usually on the chest and back. Other areas such as shoulders, arms and neck can also be affected. Sometimes there is a slight itching.

In rarer cases, skin infestation with Malassezia fungi leads to inflammation of hair follicles (Malassezia folliculitis). People with immunodeficiency (either due to medication or HIV infection) are particularly affected.

Pityriasis versicolor: causes and risk factors

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

The outbreak of bran worms occurs when the fungi suddenly multiply unchecked and spread on the skin. It is not yet known what prompted this. However, some risk factors are known that can promote the outbreak of bran lichen. This includes a warm, humid environment in which the fungi 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 root inflammation (folliculitis). Small, reddened pustules originating from hair follicles then develop on the chest, upper back, face, shoulder and neck area, which can be very itchy.

Pityriasis versicolor: investigations and diagnosis

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

  • Have you been on vacation lately and if so, where?
  • Are there skin diseases in your family?
  • Have you ever had such skin changes before?

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

The microscope helps to determine the cause of the skin changes: the doctor scrapes a sample from the affected skin areas for assessment or he sticks a piece of adhesive tape on the skin spots, presses it firmly on, then tears it off, stains it and puts it on under the microscope: In pityriasis versicolor, clusters of roundish spores of Malassezia fungi and short fungal filaments are found. 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 . Skin areas on which fungi are located fluoresce yellowish-green.

Pityriasis versicolor: treatment

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

Treatment is with antifungal agents ( antimycotics ), with local application (as a cream, shampoo) usually being 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 using a shampoo containing active ingredients – to ensure the success of the therapy and prevent recurrences, you always have to treat your head, even with a small infestation (the pathogen reservoir is in the scalp!).

In very severe cases of the disease, if the local antimycotics are not successful, a one-week systemic treatment of bran worms can be carried out: tablets with itraconazole or fluconazole, for example, are prescribed.

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

After successful treatment of pityriasis versicolor, recurrences are very common, especially in the case of a corresponding disposition.

Pityriasis versicolor: course of the disease and prognosis

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

The high risk of recurrence should be noted in the case of bran lichen . Those affected are therefore often recommended to use antifungal shampoos regularly as a preventive measure. More prevention tips:

  • Wear clothing that is as permeable to air as possible, especially in summer, that absorbs sweat from the skin or wicks it away to the outside (clothing made of synthetic fibers cannot absorb sweat well and also encourage heat to build up under clothing)
  • shower or bathe frequently using syndets (artificial washing substances that are gentle on the skin)
  • always dry yourself well after showering or bathing

These measures are also advisable in the case of an existing infection with pityriasis versicolor.

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