A dermatosis associated with bacterial overgrowth in jejunal diverticula

A patient is described with an unusual skin eruption associated with bacterial overgrowth in jejunal diverticula and malabsorption. The initial skin changes were frankly vasculitic with "target' lesions, whilst older lesions showed a psoriasiform scale and a tendency to central clearing. The illness was associated with raised levels of IgM and IgG containing circulating immune complexes and deposition of IgM and IgG in the dermis. It was suppressed by oral antibiotic therapy. There are similarities between the findings in this patient and those described in the intestinal bypass syndrome.