Skin lesions in a patient with cutaneous porphyria may include bullae, increased skin fragility, erythema and urticaria. Other conditions can produce the same lesions, creating a clinical situation that can mimic true porphyria.


Conditions that may cause a pseudoporphyria:

(1) heavy exposure to light, including use of sunbeds

(2) UVB phototherapy

(3) ingestion of a photosensitizing drugs

(4) renal failure (b ullous dermatosis of hemodialysis, see Chapter 21)

(5) SLE

(6) bullous skin disorder in an elderly patient with senile skin fragility


Photosensitizing drugs include:

(1) naproxen and other NSAIDS

(2) voraconazole

(3) dyazide

(4) imatinib mesylate (tyrosine kinase inhibitor)

(5) torsemide

(6) ciprofloxacin

(7) beta-lactam antibiotics

(8) cyclosporine

(9) oral contraceptives

(10) nabumetone

(11) flutamide

(12) isotretinoin

(13) 5-fluoruracil


A key finding in pseudoporphyia is normal porphyrin studies in urine, blood and feces.


A key differential diagnosis of pseudoporphyria is porphyria cutanea tarda (PCT).


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