Literature review. Onychomycosis.

Onychomycoses have been divided into several categories depending on the site of nail penetration by the fungus. However, not all cases entirely fit with this classification, such as potentially the deep spread of superficial fungi, suggesting alternative penetration routes. A recent European study showed that the prevalence of onychomycosis may be as high as 26.9%. The main causative agent varies according to climate; dermatophyte infections are common worldwide (70% in Europe). Mycological examination is currently the preferred diagnostic method, despite a false-negative rate of 30%. A clinical diagnostic aid that can be used alongside mycological tests is currently being developed. Newer diagnostic approaches include calcofluor, which stains fungi in nails, and molecular genetic techniques for species recognition (e.g. RFLP). Restriction fragment length polymorphism (RFLP) can also distinguish between failed treatment and reinfection. Onychomycosis can be treated with numerous oral and topical agents alone or in combination. In some studies, combination therapy appears more effective than monotherapy.