Clinical manifestations of onychomycosis

(a) Distal subungual onychomycosis The fungus, usually a dermatophyte, first invades the hyponychium and then progresses to affect the underside of the distal free-edge of the nail plate. (b) White superficial onychomycosis The fungus only invades the superficial surface of the nail plate and produces white 'islands' of infection on the nail plate. (c) Proximal subungual onychomycosis The nail plate is invaded proximally through the glabrous skin via the lower portion of the nail plate. The invasion is usually secondary to proximal nailfold candidiasis or dermatophytosis. (d) Onychomycosis associated with chronic mucocutaneous candidiasis The nail plate is distally invaded through its entire thickness by the fungus.