A patient with a 12-year history of long-term psoriatic erythroderma treated with steroids, methotrexate, and mercaptopurine was discovered to have papular mucinosis on the trunk and upper limbs. There were no systemic disorders. The possible relationship between psoriasis, steroids, antimetabolic drugs, and other factors was discussed. It is felt that the papular mucinosis is perhaps a chance association.