Presents with blistering and crusted skin lesions on the back of hands and other sun-exposed areas of the body. Other common features include skin fragility, with minor trauma causing blister formation, hypertrichosis, skin hyperpigmentation, and dark or reddish urine.
Factors that contribute to susceptibility include alcohol use, smoking, hepatitis C, HIV, iron overload, hereditary hemochromatosis gene mutations, estrogen use, and uroporphyrinogen decarboxylase (UROD) mutations.
Results from an acquired, substantial deficiency of UROD in the liver.
Diagnosis is established by finding substantial increases in porphyrins in urine or plasma.
Treatment includes repeated phlebotomy or low-dose hydroxychloroquine or chloroquine; remission can usually be achieved within 6 months.
Most common of the porphyrias.
Porphyria cutanea tarda (PCT) is a blistering cutaneous condition caused by a substantial deficiency of hepatic uroporphyrinogen decarboxylase, the fifth enzyme in the heme biosynthetic pathway. Substrates for the deficient enzyme, which are porphyrinogens (reduced porphyrins), accumulate, are oxidized to porphyrins, transported to the skin, and cause photosensitivity. PCT is usually associated with liver cell damage.
History and exam
Key diagnostic factors
- blistering skin lesions
Other diagnostic factors
- skin hyperpigmentation
- scarring alopecia
- red urine
- males, middle age, white
- alcohol use
- estrogen use
- hepatitis C
- hereditary hemochromatosis gene (HFE) mutation
- uroporphyrinogen decarboxylase (UROD) mutations
- exposure to halogenated polycyclic aromatic hydrocarbons
- reduced levels of antioxidants
- end-stage renal disease
- diabetes mellitus
1st investigations to order
- plasma total porphyrins
- plasma fluorescence emission
- urinary total porphyrins
- erythrocyte total porphyrins
Investigations to consider
- fractionation of plasma porphyrins by HPLC
- fractionation of urinary porphyrins by HPLC
- erythrocyte uroporphyrinogen decarboxylase (UROD) activity
- fecal porphyrins
- DNA studies
- serum ferritin
- liver biopsy
- skin biopsy
- serum HIV enzyme-linked immunosorbent assay
- serum hepatitis C surface antibodies
no phlebotomy contraindications
phlebotomy contraindicated or poorly tolerated
relapse after remission
Gagan Sood, MD
Department of Medicine and Surgery
Baylor College of Medicine
GS is an author of a number of references cited in this topic.
Karl E. Anderson, MD
Departments of Preventive Medicine and Community Health and Internal Medicine
University of Texas Medical Branch
KEA has received grants from the National Institutes of Health, the US Food and Drug Administration, and Alnylam Pharmaceuticals; he is an author of a number of references cited in this topic.
Robert S. Dawe, MBChB, MRCP(UK), MD(Glasgow)
Honorary Clinical Senior Lecturer
Department of Dermatology
Ninewells Hospital & Medical School
RSD declares that he has no competing interests.
Jeffrey P. Callen, MD
Professor of Medicine (Dermatology)
University of Louisville
JPC declares that he has no competing interests.
Montgomery Bissell, MD
Professor and Chief
University of California
MB declares that he has no competing interests.
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