Abstract
The clinical and mycologic features and pathogenesis of onychomycosis show that there are four clinical types distinguished by apparently unique host-parasite relationships in which the pathogenic fungus, either alone or in combination with associated microbial flora, acts in a characteristic biochemical manner to produce nail destruction. The four clinical types are distal subungual onychomycosis, white superficial onychomycosis, proximal subungual onychomycosis and Candida onychomycosis.