[How I treat... onychomycosis by topical therapy].

Onychomycosis is a frequent and challenging disease to treat. Well conducted oral therapies are commonly quite effective for a short term period. However, recurrences are frequent. Topical therapies appear globally less active. Studies in this field are rare, although the promotional advertisements to the general public abound nowadays. Various microscopic fungi (dermatophytes, yeasts, molds) should be targeted by the treatment, In addition, the distinct activity conditions of both growth and quiescence of the pathogen fungi should be influenced by the treatments. This is not frequently considered by drug companies and encountered in practice. The antifungal drug penetration inside all the nail layers is important to be performed.