Koebner Phenomenon in Lichen sclerosus et atrophicus

Fig. 1. LSA in scar after cholecystectomy. A 55-year-old woman had an appendectomy in 1964 and a cholecystectomy in 1976. The skin affection appeared in 1985 simultaneously on the inner aspects of both wrists, then in a recent scar after an incised wound (3 months old), and in an older scar in the abdominal wall after cholecystectomy (9 years old, fig. 1). The affection consisted of whitish, flat papules, 1–4 mm in diameter, with a coarse surface, which on the wrists merged into sharply demarcated irregular lesions. At the scar sites their configuration was linear, and on the abdomen, with accessory punctated lesions in the scars after stitches as well as outside them. The papules itched, and after dissemination showed no progression. There were no genital lesions. Histological findings were typical for LSA (fig. 2). The etiology of LSA is unknown, lesions usually appearing spontaneously without any precipitating factor. A preceding infection is supposed to play a provocative or localizing role in some cases of the genital affection. LSA has been reported in a vaccination site [1] and following trauma [2]. We have diagnosed LSA in two scars. Scars are sites oflocalization to psoriasis vulgaris, lichen planus and vitiligo. Other affections are localized there less frequently: mastocyto-sis [3] and erythema multiforme [4]. Probably not the localization but the age of the scar is of importance. In recent scars KP is more frequent. Letters to the Editor 77