dermatologic disorders
Nail Deformities and Dystrophies
Introduction
Deformities are often considered together with dystrophies, but the two are slightly different; deformities are generally considered to be gross changes in nail shape, whereas dystrophies are changes in nail texture or composition (eg, Onychomycosis ). About 50% of nail dystrophies result from fungal infection. The remainder result from various causes, including trauma, congenital abnormalities, Psoriasis , Onychomycosis as a cause of nail dystrophy may be obvious on examination, but often samples of the nail plate and subungual debris are taken and sent for histopathologic examination and periodic acid-Schiff (PAS) examination, culture, or, more recently, polymerase chain reaction (PCR) analysis ( General references , Nonfungal dystrophies may require a tissue biopsy of the nail plate or nail matrix to make a diagnosis. Nail dystrophy may resolve with treatment of the cause, but, if not, manicurists may be able to mask nail changes with appropriate trimming and polishes. (See also Overview of Nail Disorders .) 