Pseudoporphyria in a haemodialysis patient

A 72-year-old female with end-stage renal disease due to chronic glomerulonephritis had been treated with conventional haemodialysis for 6 years. She was referred three months ago for management of blisters and cutaneous fragility on the dorsa of both hands (Figure 1a and b). The patient denied extensive sun exposure, sun beds, or use of medications other than calcium carbonate, vitamin B complex, folic acid or erythropoietin. Haemodialysis was performed tri-weekly, 4 h per session, via an arteriovenous fistula over the left forearm, using a cellulose acetate dialyser (FB170, Nipro, Japan). The blood and dialysate flow rates were 200 and 500 cm/min, and delivered Kt/V (Daugirdas) and urea reduction rates were 1.89 and 0.79, respectively. Blood tests were negative for anti-nuclear, anti-intercellular substance and anti-basement membrane zone antibodies. Urine was also negative for porphyrin and coproporphyrin (spectrophotometry). Skin biopsy (Figure 1c) found a subepidermal vesicle with tombstone-like protruding papillary dermis, whereas immunofluorescence analysis revealed smooth linear vascular