An Atlas of Diseases of the Nail

Abstract

Readers are attracted to books by their appearance as well as their subject, and this one looks tempting, with stylish layout, clear headings and a good balance of pictures and text. The introductory chapter on nail anatomy and basic science is straightforward, although the two references are at least 7 years old. An alphabetical catalogue of nail signs and their definitions is neat and concise until ‘O’, where it digresses into aetiology and management. A classification by colour is marred by linguistic indecision, with separate sections on ‘red nails’ and ‘erythronychia’. Chapters on infections, signs of cutaneous and systemic disease, and age-related disorders contain repetitions, inaccuracies and the sort of pictures most dermatologists keep in their collections. By the time we reach ‘nail surgery’ and ‘nail cosmetics’ the temptation has worn off. It is unclear who this book is aimed at. Those keen to differentiate onychorrhexis, onychauxis and onychocryptosis (caused by ‘faulty biomechanics in the elderly’) would want more facts. It is impossible to look them up because the index, at least in my copy, stops abruptly and mysteriously at N (for nail). Those seeking treatment advice will find it unreferenced, incomplete and sometimes bizarre: examples include biotin for brittle nails, omission of amorolfine and tioconazole as topical antifungals, and digital amputation for keratoacanthoma. Illustrations of ‘epidermolysis bullosa simplex’ (which rarely affects the nails) clearly show the scarring, milia and nail dystrophy characteristic of dystrophic epidermolysis bullosa. I would like the lay public to learn that those ubiquitous little white dots and lines (‘punctate and transverse leuconychia’) are caused by minor trauma, not calcium deficiency, but despite its coffee-table format this is not a book to leave in your sitting room. Some gruesome pictures are rendered more lurid by unfortunate colour balancing, while others are mercifully overexposed. To their credit, these authors clearly love their subject. They particularly like Beau's lines, which pop up with almost the same text in three different chapters. They enthuse over longitudinal ridges and bands. They enjoy nail pits. And they cannot resist the visual economy of photographing nails next to an associated anomaly. This is sometimes effective—for example, in showing the nail and mucosal pigmentation of Laugier-Hunziger syndrome. More often one or both abnormalities are out of focus, the patients apparently gesturing incomprehensibly. At least this atlas demonstrates a trick unknown to medical photographers, that fingernails are better photographed from the palmar aspect of the hand with fingers flexed and nails approximated, than from the dorsal aspect with fingers straight and nails far apart.