[Onychomycosis : a crown jewel of dermatology].

Onychomycosis is a curable infection disease. It is widespread, but not easy to treat. Because fungal pathogens never induce immunity, the relapse rate of mycoses is generally high. The main causes are residual fungal spores in the nail and the individual susceptibility of the patient, which can hardly be influenced. Crucial for long-term therapeutic success is a sporicidal topical therapy. In severe cases ones also needs long-term, well-tolerated systemic therapy, based on accurate microbiological diagnosis of the causative agent. Presented is a three-step therapeutic approach that is easy to perform, well- tolerated and produces sustained results.