Delayed onset of overt porphyria cutanea tarda in a patient on long-term haemodialysis. A case report.

After 7 years on haemodialysis, a 37-year-old anephric man developed cutaneous lesions of the hands, arms and face, shown by skin biopsy to be compatible with porphyria cutanea tarda (PCT) (symptomatic porphyria). Elevated levels of plasma uroporphyrin and 7-COOH porphyrin were detected alongside a predominant isocoproporphyrin fraction in the faeces by means of quantitative thin-layer chromatography, confirming the diagnosis of overt PCT. The plasma uroporphyrin did not pass into the dialysate, even after chloroquine therapy. There was no evidence of hereditary PCT, chronic liver disease or iron overload, although the patient had a history of excessive alcohol consumption. The overt PCT developed after 8 months of home dialysis using softened water with high aluminium concentrations and subsided clinically and biochemically when the softened water was replaced by deionized water.