The Nail in Differential Diagnosis by Robert Baran and Eckart Haneke. ISBN: 1841845067. Hbk. 193 pages. Price: £ 90.00. Informa Healthcare, 2006.

Inspection of nails is an obligatory part of the dermatological examination, and much can be learned from nail pathology. This book is a text atlas with a comprehensive collection of 419 clinical photographs and 25 tables, divided somewhat arbitrarily into ten chapters, each focusing on a dominant pathological feature of the nail apparatus: pitting, severe nail dystrophy, subungual hyperkeratosis, onycholysis, paronychia, nail discoloration, acro-osteolysis, dual pathology, painful nail, and tumours and swellings. Thus, the diverse psoriatic nail pathology has to be dealt with in various chapters. A lot of disease entities with more or less specific nail pathology are discussed very briefly with reference to general pathological features of obvious importance for the specific diagnosis in many cases. Psoriatic pits develop from tiny areas of parakeratosis on the surface of the nail, which break out, leaving tiny pits in the plate. Nail eczema and ungual alopecia areata are due to spongiotic dermatitis of the nail matrix and nail bed with exudation of serum, giving rise to nail thickening with small pits and longitudinal striations in alopecia areata and transverse grooves in hand eczema. The dense, dermal, band-like lymphocytic infiltrate and hydropic degeneration in the basal cell layer of the matrix in lichen planus results in the characteristic longitudinal ridging with nail splitting and, eventually, nail atrophy. Nail dystrophy may in some instances be a clue to the diagnosis, e.g. Darier’s disease, pachyonychia congenita, nail-patella syndrome and yellow nail syndrome. However, the clinical response to inflammation in most disorders is multi-facetted, whereas the nail pathology is less specific. This is illustrated by the extensive listing of disorders in some tables, e.g. 148 causes of paronychia, 54 disorders related to red lunulae and the many conditions with transient or recurring disturbance of nail growth resulting in Beau lines. The term “onychogryposis” (Gk: grypos “claw”) is preferred to “onychogryphosis” (Gk: gryphos “prey bird”), although the term onychogryphosis has been used by the authors in previous texts on this subject. Some useful clinical pearls, such as Hutchinson’s sign in nail bed melanoma, are described. This book will be of interest to departments of dermatology with educational commitments and dermatologists with a special interest in this fascinating adnexal structure of obvious functional and cosmetic importance.

Flemming Brandrup

Vestergade 30

Faaborg, denmark