Inflammatory diseases of the nail unit.

inflammatory disorders of the nail unit are frequently encountered in clinical medicine and are a cause of significant morbidity. Psoriasis, lichen planus, chronic paronychia, and trachyonychia will be discussed. An approach to diagnosis and management of these disorders requires knowledge of nail unit anatomy, consideration of associated systemic manifestations, and patient education with respect to prognosis and management of factors that will maximize disease improvement. The nail unit responds with a limited number of signs to disparate clinical entities such that there is some overlap in clinical presentation between inflammatory conditions. Nail unit biopsy may therefore be useful in establishing a specific diagnosis.