Nails in systemic disease.

Nail abnormalities secondary to systemic disease are important to the dermatologist because they are readily examined and may be the initial signal that systemic disease may be present. Some of the abnormal nail findings represent part of a symptom complex that may be useful in physical diagnosis. The knowledge of the correct onychopathologic etiology may give the patient the correct nail prognosis and may prevent institution of possible incorrect lengthy and costly treatment regimens. In this article, nail signs are grouped according to the characteristics of the change and according to systemic diseases producing signs.