Onychomycosis classification

Onychomycosis may be classified according to clinical appearance of the nail into 5 subtypes

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Onychomycosis may be classified according to clinical appearance of the nail into 5 subtypes.^[1]

• Distal Subungual Onychomycosis : The most common form of tinea unguium usually caused by Trichophyton rubrum, which invades the nail bed and the underside of the nail plate.
• White Superficial Onychomycosis: Caused by fungal invasion of the superficial layers of the nail plate to form “white islands” on the plate. Accounts for only 10 percent of onychomycosis cases.
• Proximal Subungual Onychomycosis: Fungal penetration of the newly formed nail plate through the proximal nail fold. It is the least common form of tinea unguium in healthy people but found more commonly when the patient is immunocompromised.
• Endonyx subungual Onychomycosis : Fungal penetration through the full thickness of the nail from directly under the skin. The nail bed is not infected. Commonly found in immunocompromised conditions.
• Total Dystrophic Onychomycosis: Total destruction of the nail plate. It is the end result of any of the above four types.

Candidal Onychomycosis has been excluded as a separate type.