Pityriasis versicolor (PV) is a skin disease. It is a superficial mycosis, benign, due to yeast called Malassezia, part of the normal flora (saprophyte or commensal) of every human being, since he is an infant. It lives mainly in the pilosebaceous follicle.
This yeast is said to be lipophilic because its growth requires the presence of fatty acids found in sebum. PV is due to the transformation of this saprophyte yeast into a pathogenic filamentous form invading the superficial layers of the skin
The risks of getting a pityriasis versicolor
PV is not a contagious skin disease (marital cases are very rare): it is an opportunistic infection that is to say that it develops only under favorable conditions.
Among these we can mention:
Intense and greasy sweating
The seborrhea (oily perspiration) is correlated with the fact that the PV is seen especially between 18 to 40 years period seborrhea is the most important.
Thus, anything that causes significant sweating (sauna, steam room, intensive sports, wearing synthetic textiles …) can promote PV. Similarly, PV is more likely to develop during the summer in Europe and is very common in the tropics.
Diffuse forms of PV are associated with hypercorticism (Cushing’s syndrome, pregnancy, cortisone intake …).
A genetic predisposition could explain the presence of cases in members of the same parentage not living together is affected.
The symptoms of Pityriasis versicolor
The lesion of PV is a rounded patch of hue varying from buffy pink to brown “café au lait”, with clear boundaries, a few millimeters in diameter. It starts most often around a hair follicle (the “reservoir” area of Malassezia) and it grows centrifugally.
The confluence of the spots can range from a “drop” appearance to large polycyclic contours.
After a few weeks of evolution, or during a solar exposure, the lesions become white and are particularly visible on tanned or black skin.
If you look closely at the lesions or gently scratch them, they are finely scaly (“furfuraceous squames”).
The lesions sit mainly in the cutaneous zones richest in sebaceous glands: upper part of the back, thorax, shoulders, neck, arm, sub-mammary region…
Only palms and plants are never touched.
The lesions do not itch in the vast majority of cases
Examination in UV light with a Wood lamp reveals a pale greenish yellow fluorescence, but fluorescence may be lacking.
Treatments of pityriasis versicolor
The stop contributing factors is important to limit the risk of recurrence (oily cosmetics, occlusive or synthetic clothing …).
The doctor usually prescribes ketoconazole single- dose foaming gel (Ketoconazole, Ketoderm® …) to apply hair to the feet and let it act for 5 minutes.
The high frequency of recurrence, reaching 60% in the first year and 80% after 2 years is sometimes due to the persistence of contributing factors.
In case of frequent recurrence despite the eradication of the favoring factors, some doctors prescribe a maintenance treatment with one or two applications per week for several months; others prefer a preventive treatment which consists in resuming the local treatment before or at the beginning of the summer season.
The oral ketoconazole (Nizoral) can prevent relapses in a dose of 400 mg once / month or 200 mg / day for 3 consecutive days once a month. Similarly for itraconazole (Sporanox) at a dose of 400 mg once a month for 6 months.