A case of reticular erythematous mucinosis successfully treated with topical and oral steroids

A 65-year-old Japanese woman with an eight-month history of reticular macular erythema on the midlines of her back and chest was referred to our hospital. She had a history of MALT lymphoma and Takayasu arteritis, and had been treated with oral prednisolone (5 mg/day) for Takayasu arteritis. Histopathological examination of a biopsy from the erythema revealed perivascular lymphocytic infiltrates and mucin deposition in the superficial dermis. Based on the clinical and histopathological findings, a diagnosis of reticular erythematous mucinosis (REM) was made. Antimalarial agents are known to be effective in the treatment of REM, but antimalarial agents were not approved in Japan at the time. Thus, although topical and oral steroids are generally not effective against REM, we administered topical betamethasone butyrate propionate to the lesions. Soon after the administration of the topical steroid, the lesions improved gradually. Two months after the administration, oral prednisolone was increased to 10 mg/day, and the lesions almost completely cleared.