Lack of effect of dimethylsulphoxide in cutaneous amyloidosis.

OBJECTIVE: To evaluate dimethylsulphoxide (DMSO) as a topical therapeutic agent for the treatment of two major variants of primary, localized, cutaneous amyloidosis -- macular amyloidosis (MA) and papular/lichen amyloidosis (LA) -- using a monocentric, open, prospective trial.

METHODS: A total of 25 patients with histopathologically proven cutaneous amyloidosis - MA, LA and BA (biphasic amyloidosis) (13 MA, seven LA, five BA) were requested to undertake a once daily application of either 50% or 100% DMSO for 12 weeks. Progress was regularly assessed with a scoring system for pruritus, pigmentation and papules.

RESULTS: In 17 (68%) cases, the scores for pruritus decreased but never completely disappeared in any of the patients. Lightening of the pigmentation was noted in only six (24%) cases and the scores for the papules were decreased in only two out of 12 (16.6%) patients. Post-treatment skin biopsies did not reveal a reduction/disappearance of the amyloid deposits. In the follow-up period, the relapse rate was 100%.

CONCLUSION: DMSO does not have an anti-pruritic effect or amyloid-dissolving properties. As the results are partial and transient, it is concluded that DMSO is not a satisfactory treatment for cutaneous amyloidosis.