Rheumatoid Arthritis Support

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.

In contrast to PCT, EPP usually begins in childhood with a history of photosensitivity, often described as a burning sensation immediately after sunlight exposure.

Clinically, EPP is characterized by erythema, edema, shallow scars, and waxy induration of the skin, particularly on the face.

Pseudoporphyria that clinically mimics EPP has been described almost exclusively in children taking naproxen for juvenile rheumatoid arthritis. Naproxen-induced pseudoporphyria seems to have a dimorphic presentation with the PCT-like pattern more often seen in the adult population and the EPP-like pattern more commonly seen in children, although some overlap has been documented.


Adapted from the Wikipedia article Pseudoporphyria, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki