[Nail disorders in daily practice].

Familiarity with common nail disorders enables the clinician to diagnose and treat nail disorders and to recognize red-flag conditions. Knowledge of the anatomy of the nail unit is essential to understand the origin of nail disorders. This article focuses on neoplasms, abnormalities of nail color and shape, infections, and inflammatory conditions of the nail unit. There are various neoplasms of and around the nail unit, like squamous cell carcinoma (in situ), melanoma, and benign neoplasms such as mucous cyst, subungual exostosis, glomus tumor, onychopapilloma and fibro(kerato)ma. The most common deviating colors of the nail are red, white and brown-black. Abnormalities of nail color and shape may indicate an underlying systemic disease. Infections of the nail unit include onychomycosis, acute paronychia, pseudomonas nail infection and verruca vulgaris. The inflammatory conditions we discuss in this article are chronic paronychia, psoriasis, alopecia areata and lichen planus.