Examining the importance of laboratory and diagnostic testing when treating and diagnosing onychomycosis.

Onychomycosis is a fungal nail infection caused primarily by dermatophytes. Several other nail disorders, including psoriasis, can simulate onychomycosis. Accurate diagnosis is therefore vital for the ongoing treatment and management of onychomycosis and to avoid misdiagnosis and treatment delay, which can be both lengthy and costly. Often, a combination of histologic and laboratory techniques is used to obtain an accurate diagnosis. The potential diagnostic challenges associated with the differential diagnosis of onychomycosis caused by dermatophytes and the most common techniques used to confirm the diagnosis are discussed.