Mold onychomycosis often can be clinically suspected because of the presence of periungual inflammation. Treatment with systemic antifungals is very effective in onychomycosis caused by Aspergillus sp. Scopulariopsis brevicaulis and Fusarium sp. infection are difficult to eradicate and treatment with systemic antifungals should always be associated with topical treatment with nail lacquers. Candida onychomycosis is always a sign of immunodepression. Systemic treatment with itraconazole or fluconazole is usually effective, but relapses are very common.