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).
