Malassezia is a genus of fungi or yeasts, normally living on the human skin. There are about the 10 types of this yeast and they cause Pityriasis versicolor, Pityriasis folliculitis, seborrhoeic dermatitis and dandruff. Babies and adults on the lipid substitution therapy also have these fungi in the blood.Disorders
Pityriasis versicolor is a condition when skin becomes hyper or hypo-pigmented. Malassezia cause fungal infection of the skin and leads to skin lesions, visible as white, pink or brown patches, covered with dry skin that looks like dandruff. Most lesions appear on the upper body, arms and shoulders, and rarely affect neck or face. Caucasians experience hyper pigmentation and Aborigine in Australia hypo pigmentation. Skin changes are visible under the ultraviolent (UV) light and they have greenish fluorescence.
Pityriasis folliculitis appears as bumps and pimples on the chest, upper arms or the back. Rarely, this skin changes happen on the neck or the face. They are often connected to the exposure to the sun. The condition is usually treated with imidazole creams, but some cases require oral anti-fungal medications, like ketoconazole or itraconazole. Doctors also recommend prophylactic therapy.
Dandruff and seborrhoeic dermatitis are usually caused by Malassezia furfur (M.furfur). There are some risk factors associated with these disorders, like genetics, sebum and skin changes, occlusions and also emotional factors. Patients suffering from AIDS or Parkinson’s disease are also quite often infected with these fungi. These conditions appear as red lesions and scaling on the scalp, face, eyebrows or ears, and might spread to upper body. Therapy includes imidazole or ketoconazole locally. Most cases need re-treatments.
People using catheter or those on the lipid replacement treatment may be affected by fungaemia. Diagnosis
Skin scrapings, blood and catheter culture are commonly used to diagnose these fungi. Using a microscope, laboratory can identify the specific M.furfur characteristics and identify the fungus. In the cases of suspected fungaemia, it is usually necessary to cultivate culture preparations.Anti- fungal Treatment
Pityriasis versicolor is treated with imidazole solution or some other local preparation, and sometimes ketoconazole shampoo. Shampoos with zinc pirithione and selenium sulfide lotion have also been proven helpful in this condition. Widespread lesions need oral treatment with ketoconazole or itrazonazole.
Skin pigmentation get back to normal after the treatment, but it needs time to heal, sometimes even several months. Because the relapses are common for this type of disorder, prophylactic use of local preparations is necessary. Usually, use of the preparation one or two time per week is enough.