Local DMSO treatment of macular and papular amyloidosis

Abstract

Macular amyloidosis (MA) and lichen amyloidosus (LA) are the two major variants of the primary cutaneous amyloidoses which present with severe and therapy resistant itching. Various therapeutic modalities such as antihistamines, intralesional injection or topical application of corticosteroids, etretinate, UVB irradiation and dermoabrasion have been employed with variable success. Recently, in a few case reports authors have observed encouraging beneficial clinical effects by using topical dimethyl sulphoxide (DMSO). In our study 10 patients with either MA or LA or biphasic amyloidosis were treated with a 50% solution of DMSO in water. 9 of them showed marked clinical improvement at the end of 6-20 weeks of treatment. Degranulation and depletion of the mast cells by DMSO is the most probable explanation for the rapid improvement of itching beginning within the first week of therapy. Remarkable flattening of the lichenoid papules which was obtained within 11 weeks of treatment is interpreted as a result of the improvement of itching and the related scratch effect. Histological examination after treatment revealed no disappearance of amyloid deposits in the papillary dermis. In the follow-up period relapses of itching and papules were observed. Therefore further studies are needed to find out the optimal procedure of therapy.