Most common of the porphyrias.
Results from an acquired, substantial deficiency of uroporphyrinogen decarboxylase (UROD) in the liver.
Recognised by 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 haemochromatosis gene (HFE) mutations, oestrogen use, and UROD mutations.
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.
Porphyria cutanea tarda (PCT) is a blistering cutaneous condition caused by a substantial deficiency of hepatic uroporphyrinogen decarboxylase (UROD), the fifth enzyme in the haem biosynthetic pathway. Substrates for the deficient enzyme, which are porphyrinogens (reduced porphyrins), accumulate, are oxidised to porphyrins, transported to the skin, and cause photosensitivity.  Most cases are associated with liver cell damage.
Department of Medicine and Surgery
Baylor College of Medicine
GS is an author of a number of references cited in this monograph.
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 monograph.
Honorary Clinical Senior Lecturer
Department of Dermatology
Ninewells Hospital & Medical School
RSD declares that he has no competing interests.
Professor of Medicine (Dermatology)
University of Louisville
JPC declares that he has no competing interests.
Professor and Chief
University of California
MB declares that he has no competing interests.
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