The role of trichoscopy beyond hair and scalp diseases. A review.

Abstract

Trichoscopy is a diagnostic tool for hair and scalp diseases. It was recently shown that it also allows the identification of features associated with disorders that typically don't affect the scalp. The aim of this article was to analyze and outline the usefulness of trichoscopy in suspecting such diseases. Connective tissue diseases were the most investigated systemic diseases in regard to trichoscopy. The most common features of systemic lupus erythematosus, systemic sclerosis, and dermatomyositis are thick arborizing and tortuous vessels. Avascular areas are present in systemic sclerosis. Spermatozoa-like vessels may be observed in cutaneous T-cell lymphomas, while salmon-colored areas with arborizing and linear vessels can be seen in patients with cutaneous B-cell lymphomas. In patients with advanced multiple myeloma, follicular spicules may be observed. Trichoscopic features of angiosarcomas include pink areas, red polymorphic areas, and dark red to purple areas. Polymorphous vessels and yellowish areas on a pink background are the predominating trichoscopy features of metastases of malignant tumors to the scalp. Cutaneous sarcoidosis is characterized by orange-colored areas and telangiectasias. Systemic amyloidosis may manifest with salmon-colored perifollicular halos, while the most common trichoscopic features of syphilitic alopecia are: a decreased number of hairs per follicular unit, vellus hairs, background erythema, focal atrichia and yellow dots. In conclusion, dermatologists may suspect some systemic diseases on the basis of trichoscopy findings.