Pseudoporphyria

Pseudoporphyria is a bullous photosensitivity that clinically and histologically mimics porphyria cutanea tarda.:524 The difference is that no abnormalities in urine or serum porphyrin is noted on laboratories. Pseudoporphyria has been reported in patients with chronic renal failure treated with hemodialysis and in those with excessive exposure to ultraviolet A (UV-A) by tanning beds. Pseudoporphyria is a bullous photosensitivity that clinically and histologically mimics porphyria cutanea tarda.:524 The difference is that no abnormalities in urine or serum porphyrin is noted on laboratories. Pseudoporphyria has been reported in patients with chronic renal failure treated with hemodialysis and in those with excessive exposure to ultraviolet A (UV-A) by tanning beds. Pseudoporphyria is clinically characterized by increased skin fragility; erythema; and the appearance of tense bullae and erosions on sun-exposed skin, which are identical to those seen in patients with PCT. However, a clinical pearl that may prove helpful in differentiating between pseudoporphyria and PCT is that the classic features of hypertrichosis, hyperpigmentation, and sclerodermoid changes found with PCT are unusual with pseudoporphyria.A second clinical pattern of pseudoporphyria has a similar presentation to erythropoietic protoporphyria (EPP), an autosomal dominant porphyria resulting from a reduced activity of ferrochelatase.