[Can we evaluate the frequency of onychomycosis?].

Onychomycosis represents one of the most common nail diseases. Difficult to bear by some patients, onychomycosis is one of the most frequent reasons for consulting by lack of uniformity and group-control a mycological centre. However, frequency of onychomycosis is miss appreciable. The studies of prevalence concern the general population (2 to 13 per cent according to the different authors) consulting a medical practitioner or specialist (dermatologist). Recent surveys done a large scale in Europe in adults indicated high prevalence: 20 to 30 per cent, depending on whether the investigator is a general practitioner or a dermatologist. In any case, all the studies concur in the opinion that onychomycosis has been in constant progression over the last twenty years. Rarely observed in children, frequent in adults, onychomycosis principally affects particularly the elderly. In Western Europe and in North America, onychomycosis involves principally the feet--especially in males. By contrast, in Southern Europe, in the Middle and Far East, the prevalence is highest in women's fingernails (often associated with paronychia). Among the factors promoting fungal nail invasion, some are local depending on the patient (trophic troubles and circulatory impairment overlapping of digits, etc.), some are due to general factors such as immunosuppression, diabetes mellitus or psoriasis. There are also behavioural factors (occupation, lifestyle, sports) which favor the meeting with the pathogenic fungus.