title: Pseudoporphyria: a clinical and biochemical study of 20 patients.
abstract: OBJECTIVE
  To describe the clinical and laboratory findings in patients with pseudoporphyria.
  
  
  METHODS
  This retrospective review identified 261 patients with either porphyrin metabolism abnormalities or pseudoporphyria who were seen at the Mayo Clinic in Rochester, Minn, between 1992 and 1996. All patients with documented porphyria cutanea tarda (PCT), noncutaneous porphyrias, or variegate porphyria were excluded.
  
  
  RESULTS
  Twenty patients had active cutaneous lesions resembling PCT with no diagnostic laboratory abnormalities. The major presenting clinical features were blistering in 19 patients (95%), scarring in 14 (70%), photosensitivity in 13 (65%), skin fragility in 13 (65%), and milia in 8 (40%). Histologically, of 17 patients tested, 12 (71%) had classic findings of subepidermal separation with festooning of dermal papillae. None of the 11 patients tested had hepatitis B or C. In all 20 patients, porphyrin profiles were nondiagnostic. Of 16 patients for whom follow-up was available, 11 reported persistent symptoms for a mean of 2.5 years after evaluation. Five patients were free of symptoms 1 week to 6 months after discontinuation of the presumed offending agent.
  
  
  CONCLUSIONS
  Pseudoporphyria mimics the cutaneous symptoms of PCT in the setting of normal or near-normal porphyrin levels in the serum, urine, or stool. Despite efforts to discontinue an offending medication, symptoms may persist indefinitely.
authors.affiliation: Department of Dermatology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
authors.forename: C F
authors.initials: CF
authors.lastname: Schanbacher
authors.forename: E R
authors.initials: ER
authors.lastname: Vanness
authors.forename: M S
authors.initials: MS
authors.lastname: Daoud
authors.forename: A
authors.initials: A
authors.lastname: Tefferi
authors.forename: W P
authors.initials: WP
authors.lastname: Su
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D016347:Medical Records Systems, Computerized; D008875:Middle Aged; D011164:Porphyrias / Q000378:metabolism* / Q000473:pathology; D011166:Porphyrins / Q000097:blood*; D012189:Retrospective Studies
chemical_list: D011166:Porphyrins