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Onychomycosis (cont.)

Summary of Common Types of Onychomycosis

Characteristics of Common Types of Onychomycosis (OM)

Characteristic DLSO PSO WSO
Frequency Most common Generally uncommon but frequent in AIDS patients Makes up 10% of cases of OM
Progress of infection Infection begins with invasion of the space under the nail edge where the nail separates from the nail bed (called the hyponychium) Infection begins at the nail fold (where the nail meets the finger or toe) and affects newly forming nail Infection begins at the surface of the nail (nail plate) and progresses to deeper layers
Clinical appearance Separation of the nail from the nail bed (onycholysis), thickening of the area under the nail (subungual hyperkeratosis) Subungual hyperkeratosis, white discoloration (leukonychia), separation of the nail from the nail bed (onycholysis), and destruction of the nail unit White areas on the nail surface, eventually involving the entire nail surface
Most common causative organism Trichophyton rubrum Trichophyton rubrum Trichophyton mentagrophytes, Aspergillus terreus, Acremonium roseogriseum, Fusarium oxysporum
Affected nails Toenails most commonly affected but may affect fingernails as well Much more common on the toenails, rarely affects fingernails Mainly affect toenails

The term total dystrophic onychomycosis is not a subtype, but is, instead, the final stage of any of the previously described forms of onychomycosis, candidal onychomycosis, or both

Medically reviewed by Norman Levine, MD; American Board of Dermatology


Onumah, Neh. "Nail Surgery." Jan. 25, 2012. <>.

Tosti, Antonella. "Onychomycosis." May 5, 2010. <>.

Medically Reviewed by a Doctor on 11/5/2014

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Onychomycosis (OM) refers to a fungal infection that affects the toenails or the fingernails.

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