blistering

A 44-year-old Caucasian male with a past medical history of hepatitis C presents with a complaint of pain, swelling, and skin blistering of his hands. He also notes skin sores on his nose, lower lip, and the tops of his ears. The patient claims that these have become progressively worse since starting work a month ago in outdoor construction. The patient denies the use of medications or illicit drugs and denies any medical allergies. He admits to tobacco use and daily alcohol use. The patient denies any other symptoms.


Vitals: BP 149/695; HR 103; RR 18; Temperature 98.9°F

General: The patient is in moderate distress secondary to pain.

HEENT:

  • Normocephalic; pupils equal, round, and reactive to light and accommodation
  • No oral mucosa lesions

Neurologic:

  • Alert and oriented to person, time, and place
  • No focal deficits, strength rated “five” on a five-point scale, sensation normal

Skin:

  • Tense vesicles, bullae, and erosions noted on the dorsum of bilateral hands, upper and lower lips, nose, and superior aspects of bilateral ears
  • Fingernails exhibit photo-onycholysis

The remainder of the exam is unremarkable

Complete-blood-count and coagulation studies were within normal limits.

Comprehensive metabolic panel was only notable for mild elevation in transaminases.

AST: 100 units/L

ALT: 60 units/L

Porphyria cutanea tarda

Porphyria cutanea tarda (PCT) is the most common form of porphyria that presents as painful blistering on sun-exposed areas of the skin, commonly the dorsum of hands, forearms, the back of the neck, and the face. Other clinical manifestations include hypertrichosis of the face, scarring, skin fragility, and photo-onycholysis (separation of nails from nailbed).

This disorder is caused by a deficiency in the enzyme uroporphyrinogen III decarboxylase (UROD). In most cases of PCT, liver toxicity (hepatitis C, alcohol abuse, exogenous estrogen exposure, hemochromatosis, other causes of iron overload, or hepatic tumors) causes or exacerbates the effects of the enzymatic deficiency. Uroporphyrins subsequently accumulate in the liver and the skin. At certain wavelengths of light (such as sunlight), the porphyrins in the skin release energy, and the reactive oxygen species cause tissue damage. Liver involvement includes focal steatosis, focal lobular necrosis, and portal inflammation and fibrosis.

Serum porphyrins are the initial screening test, while performing a 24-hour urine/stool porphyrin test is confirmatory.

A skin biopsy may be useful as well.

These studies confirmed the diagnosis in this patient.

Management involves serial phlebotomy, sun-protective clothing, sunscreen usage, and smoking and alcohol avoidance. Alternative therapies includes antimalarials, such as hydroxychloroquine.

Take-Home Points

  • Porphyria cutanea tarda manifests as painful blistering in sun-exposed areas.
  • Check for urine porphyrins and liver toxicity when suspicious for porphyria cutanea tarda.
  • Therapy includes phlebotomy and sun-protective practices.
  1. Liu LU, Phillips J, Bonkovsky H; Porphyrias Consortium of the Rare Diseases Clinical Research Network. Familial Porphyria Cutanea Tarda. 2013 Jun 6 [Updated 2016 Sep 8]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2020. PMID: 23741761
  2. Singal, A. K. (2019). Porphyria cutanea tarda: Recent update. Molecular Genetics and Metabolism128(3), 271–281. doi: 10.1016/j.ymgme.2019.01.004. PMID: 30683557

Justin Rich

Justin Rich

Medical Student
University of South Alabama College of Medicine
Justin Rich

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Michael Sternberg, MD

Michael Sternberg, MD

Professor
Department of Emergency Medicine
University of South Alabama
Michael Sternberg, MD

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