[Loose anagen hair syndrome].

In 1984, Zaun described a new type of pilary dysplasia characterized by easily pluckable hair. We were able to observe three patients with this anomaly, and this paper is an attempt at reviewing the subject on the basis of these new cases compared with those previously published. Clinical features. The major sign of the anomaly is that hairs can be pulled off in tufts easily and painlessly, and promptly grow again (our cases). In all cases reported so far the hair was blond or dark-blond; in some patients it is described as scintillating (our cases). The hair shaft is usually thin (one of our cases), but it may be of normal caliber (two of our patients). In the occipital region the hairs are entangled, dry and short (our cases). They are implanted wide apart or at normal intervals (our patients); areas of alopecia are sometimes encountered (our cases). Hair growth may be slow (one of our cases) or of normal speed (two of our cases). The eyelashes and eyebrows, as well as other body hairs, are normal in all patients (fig. 1). Microscopy. The trichogram is exclusively composed of anagenic and dystrophic roots (our cases). Pathological examination by biopsy of the scalp is characteristic: transverse and oblique sections of the follicles show that the hairs are oval, triangular or trapezoidal in shape (fig. 7). Alterations of the inner epithelial sheath are also present, including keratinization and early decomposition (fig. 8), lack of complementation (fig. 7) and fissures between the cuticle of the inner epithelial sheath and of the hair, in the keratogenic area (fig. 9). (ABSTRACT TRUNCATED AT 250 WORDS)