Pathology of the Finger Nail in Psoriasis.

Summary.— Psoriasis of the finger nail produces metaplastic change of the nail matrix and nail bed to skin‐like epithelium, following which the histological changes are essentially similar to those seen in the skin. The resulting lesions of the finger nail are of 2 types: (1) Nail plate abnormalities, the nature of which depends upon the site and the duration of disease in the matrix; (2) Nail bed abnormalities, consisting of onycholysis, subungual keratosis and splinter haemorrhages.