The case of a patient with the rare combination of psoriasiform erythroderma, pustular psoriasis and arthritis is presented. The patient, now a 10½ -year-old boy, has had his skin disease since birth and a progressing arthritissince the age of five. Several skin biopsies have confirmed thediagnosis of pustular psoriasis. Methotrexate has had a beneficial effect on the skin; whether methotrexate also will influence his arthritis remains to be seen.