Lichen amyloidosus: a study of clinical, histopathologic and immunofluorescence findings in 30 cases.

BACKGROUND: Lichen amyloidosus (LA) is a primary localized cutaneous amyloidosis characterized clinically by discrete hyperkeratotic hyperpigmented papules and histologically by deposition of amyloid material in previously normal skin without any evidence of visceral involvement. AIMS AND OBJECTIVES: The aim of this work was to study the etiology, clinical features, histopathology and direct immunofluorescence findings in LA. METHODS: A prospective study of 30 patients with clinical, histological and immunofluorescence findings suggestive of LA was undertaken. After a detailed history and clinical examination, two punch biopsies for histopathology and immunofluorescence were taken. RESULTS: Of the 30 patients, 19 (63.3%) were males and 11 (36.7%) were females with duration of LA ranging from 6-20 months. Pruritus was the presenting symptom in 27 (90%) patients. Shin was involved in 26 (86.7%) followed by arms in three (10%) and back in one (3.3%). Seventeen patients (56%) had used scrubs for more than 2 years. Histopathology, direct immunofluorescence and Congo red staining detected amyloid in all cases. CONCLUSIONS: LA commonly presents over the shins as pruritic discrete hyperpigmented papules. Familial predisposition and friction may have a pathogenic role. Histopathological examination is very useful in the detection of amyloid which may be supplemented with direct immunofluorescence and Congo red staining.