Porphyria cutanea tarda

Porphyria cutanea tarda
Blister on the hand of a person with porphyria cutanea tarda
SpecialtyDermatology

Porphyria cutanea tarda (PCT) is a form of long-term porphyria characterised by fragile skin and sore blisters in areas of skin that receive higher levels of exposure to sunlight, such as the face and backs of the hands.[1] These blisters burst easily resulting in erosions, crusts, and superficial ulcers.[1][2] There is often associated darkened skin color and extra facial hair growth.[1] Healing is typically slow, leading to scarring and milia, while changes such as hair loss, and alterations in nails may also occur.[1] A slightly purplish tint may be seen around the eyes.[1] Scleroderma-like thick skin may develop over fingers, scalp, behind the ears, at the back of the neck, or in the front of the chest.[1][2] The urine may appear dark.[2] Unlike other porphyrias, PCT does not cause severe illness.[2]

The disorder results from a deficiency of uroporphyrinogen III decarboxylase, used in the production of heme, a vital component of hemoglobin.[1] It is generally divided into three types; familial, non-familial, and acquired.[1] The condition can be related to liver disease and a history of excessive alcohol consumption.[1] It is a recognised complication of hepatitis C.[1] Other associated conditions include type 2 diabetes, metabolic syndrome, HIV, SLE, and haemochromatosis.[1][2] Smoking, and the use of estrogen in males with prostate cancer and females on combined contraceptive pill may also trigger PCT.[3] Renal dialysis may cause retention of porphyrins and cause PCT.[2]

Tests generally include blood tests; liver function test, kidney function, complete blood count, ferritin, hepatitis B, hepatitis C, HIV, and HbA1C.[1][3] Other tests may include checking urine for pinky-red fluorescence with Wood's lamp, testing a 24-hour urine for porphyrins, and skin biopsy.[1][2] Pseudoporphyria may appear similar.[1] PCT may be distinguished from epidermolysis bullosa acquisita by the presence of excess hair.[3] Treatment for PCT focuses on removing all contributing factors, including alcohol, specific medicines, and managing hepatitis C and metabolic syndrome if applicable.[1] Though typical sunscreens may provide limited protection, more effective alternatives are barrier sunscreens.[1] Wearing a hat and gloves can help.[1] Other treatment options include phlebotomy.[3] An alternative is a low dose of an anti-malarial treatment.[3] Treating co-existing hepatitis C generally helps.[1] Without removing triggering factors, PCT tends to recur.[2] Recurrence in the year following phlebotomy treatment is not common.[3] Individuals with PCT have a 3.5 times higher risk of developing hepatocellular carcinoma.[1]

PCT is rare, though it is the most common subtype of porphyria.[1][4]

  1. ^ a b c d e f g h i j k l m n o p q r s t James, William D.; Elston, Dirk; Treat, James R.; Rosenbach, Misha A.; Neuhaus, Isaac (2020). "36. Disturbances of pigmentation". Andrews' Diseases of the Skin: Clinical Dermatology (13th ed.). Edinburgh: Elsevier. pp. 520–521. ISBN 978-0-323-54753-6.
  2. ^ a b c d e f g h Oakley, Amanda (26 October 2023). "Porphyria cutanea tarda". DermNet. Archived from the original on 29 November 2024. Retrieved 25 March 2025.
  3. ^ a b c d e f Saavedra, Arturo; Roh, Ellen K.; Mikailov, Anar (2023). "10. Photosensitivity, photo-induced disorders, and disorders by ionizing radiation". Fitzpatrick's Color Atlas and Synopsis of Clinical Dermatology (9th ed.). New York: McGraw Hill Professional. pp. 220–223. ISBN 978-1-264-27801-5.
  4. ^ "Porphyria Cutanea Tarda - Symptoms, Causes, Treatment | NORD". rarediseases.org. Retrieved 29 March 2025.
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