Bullous pemphigoid and rheumatoid arthritis: Is there disease association?

Sir, We would like to report an unusual case of a patient with chronic rheumatoid arthritis (RA) who 20 yrs later developed severe bullous pemphigoid (BP). BP and RA are rarely found in the same patient. We discuss the differential diagnosis of the bullous skin eruption and we suggest that co-existence of these 2 autoimmune diseases may be more than a chance event. A 50 yr old female was hospitalised with a 6 week history of prur i tus and progress ive skin bl is ter ing involving the forearms, trunk and legs. She had a 20 yr history of severe RA. She had never been treated with penicillamine. Skin examination revealed widespread erosions, a few tense bullae and a positive Nikolsky's sign; there were no oral lesions. She had changes of longstanding nodular RA that was clinically inactive. The initial clinical impression was of pemphigus vulgaris based on the widespread erosions and the positive Nikolsky's sign. Laboratory investigations showed: haemoglobin: 8.7g/dl, MCV: 61.9, MCH: 20.4 and a haematocrit of 0.26. White cell and platelet counts were normal. The ESR was 24mm/h. S e r um fe r r i t in was 120mmol / l . Rout ine b iochemis t ry and complement levels were normal. Rheumatoid factor (RF) was positive: 1:2560 and serum epithelial anti-basement membrane zone (anti-BMZ) IgG antibody was also positive. Cultures of the skin lesions grew Staphylococcus aureus. Skin biopsy revealed a subepidermal bl ister with an inf lammatory infiltrate of eosinophils, neutrophils and mononuclear cells. Direct irnmunofluorescence (DIF) of the perilesional skin showed C3, IgG and IgM in a con t i nuous band at the dermoepidermal junction (DEJ). The patient was treated with 60 mg prednisolone and had slow resolution of the skin lesions. Further blistering occurred on reduction of the corticosteroids to 40mg/day and azathioprine 100mg/ day was later introduced. Resolution of the bullae and healing of the erosions was possible over a 3 month period. Discontinuation of therapy was possible six months later but relapse led to reintroduction of both prednisolone and azathioprine again with good control. A diagnosis of BP