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Late cutaneous porphyria: causes, symptoms, diagnosis, treatment
Medical expert of the article
Last reviewed: 05.07.2025
Porphyria cutanea tarda is a relatively common disorder that primarily affects the skin. Iron ions play a key role in the pathogenesis of this form of porphyria. Clinical symptoms include brittleness and fragility of the skin and the development of blisters on sun-exposed areas of the skin or bruises. An increase in liver disease is observed in the population of patients with this form of porphyria. Precipitating factors include excessive sun exposure, alcohol consumption, estrogens, previous hepatitis C infection, and possibly HIV infection; however, drugs that do not contain iron and estrogens are not dangerous. Diagnosis is based on plasma fluorescence or detection of porphyrins in urine and stool tests. Treatment involves lowering the iron content in the blood using phlebotomy, administering chloroquine, and increasing the excretion of porphyrins using hydrochloroquine. Prevention consists of patients being advised to avoid direct sunlight on their skin and to avoid drinking alcohol and taking iron-containing medications.
[ Causes of Porphyria Cutanea Late
Porphyria cutanea tarda (PCT) results from a genetic deficiency of uroporphyrinogen decarboxylase. Porphyrins accumulate in the liver and are transported to the skin, where they cause increased photosensitivity. A 50% decrease in UPGD activity in heterozygous patients is not sufficient to cause clinical symptoms of PCT. Other factors disrupting enzymatic activity must be present for symptoms to occur. Iron plays a key role, probably by generating oxygen free radicals that inhibit UPGD by oxygenating their substrate; hemochromatosis is thus a significant risk factor. Alcohol, estrogen, and chronic viral infection probably also influence the pathogenetic pathways of this form of porphyria by increasing iron ion activity in the liver. Various medications that can trigger acute porphyria are not triggers for PCT.
Liver disease is common in porphyria cutanea tarda and is a consequence of partial accumulation of porphyrin, development of infectious hepatitis C, concomitant hemosiderosis, or alcohol abuse. Cirrhosis occurs in less than 35% of patients, and hepatocellular carcinoma in 7-24% (more common in middle-aged men).
The two known forms of the disease, type 1 and type 2, have a similar onset, rapid progression, the same symptoms, and the same treatment. Other, less common forms also occur. Their incidence is approximately 1/10,000.
In type 1 porphyria cutanea tarda (sporadic), the decarboxylase deficiency that develops is limited to the liver. This type usually becomes clinically apparent in middle age or later.
In type 2 porphyria cutanea tarda (familial), the developing decarboxylase deficiency is hereditary, transmitted in an autosomal dominant manner, with limited penetrance. The deficiency develops in all cells, including red blood cells. Its clinical manifestations are observed earlier than in type 1, sometimes from childhood.
Secondary PCT-like conditions (pseudoporphyria) may occur with the use of some photosensitizing drugs (e.g., furosemide, tetracyclines, pentanoic acid, sulfonamides, some NSAIDs). Because of poor renal excretion of porphyrins, some patients are placed on chronic hemodialysis and develop skin pathology similar to porphyria cutanea tarda (pseudoporphyria of end-stage renal failure).
Symptoms of Porphyria Cutanea Late
Patients develop thinning and brittle skin, mainly in sun-exposed areas. The skin's increased sensitivity to light decreases: patients do not always develop characteristic symptoms when exposed to the sun.
Pemphigus develops spontaneously or after minor trauma. Associated skin erosions and ulcerations may be complicated by secondary infection; they heal slowly, leaving atrophic scars. Sun exposure sometimes results in erythema, edema, and itching. Conjunctival hyperemia may develop, but other mucous membranes remain intact. Areas of hypopigmentation or hyperpigmentation may appear, as may facial hypertrichosis and pseudosclerodermoid changes.
Diagnosis of porphyria cutanea tarda
In some cases, otherwise healthy individuals develop thinning and fragility of the skin and a vesicular rash, which are indicative of PCT. Therefore, differential diagnosis of acute porphyria with cutaneous symptoms [variegate porphyria (VP) and hereditary coproporphyria (HCP)] is extremely important, since the use of porphyrinogenic drugs in patients with VP and HCP may cause the development of neurovisceral symptoms. Previously noted neurological, psychosomatic symptoms or abdominal symptoms of unknown etiology may be indicative of acute porphyria. Also, one should keep in mind the patient's history of using chemicals that can cause pseudoporphyria symptoms.
Although all porphyrias that cause skin lesions have elevated plasma porphyrin levels, elevated urinary uroporphyrin and heptacarboxylporphyrin and fecal isocoproporphyrin support PCT. Urinary levels of the porphyrin precursor porphobilinogen (PBG) and usually 5-aminolevulinic acid (ALA) are normal in PCT. Red blood cell UPGD activity is also normal in type 1 PCT but is elevated in type 2.
Due to the fact that the concomitant development of infectious hepatitis C is characteristic of this pathology and the clinical symptoms of hepatitis are smoothed out or not determined, it is necessary to determine serum markers for hepatitis C (see p. 292).
What do need to examine?
How to examine?
Treatment and prevention of porphyria cutanea tarda
Two different therapeutic approaches are possible: decreasing iron stores in the body and increasing porphyrin excretion. These two treatment approaches can be combined.
Iron depletion by phlebotomy and bloodletting is usually effective. The patient loses about 0.5 liters of blood every 2 weeks. When the serum iron level falls slightly below normal, phlebotomy is stopped. Usually only 5-6 treatments are needed. Urine and plasma porphyrin levels decrease gradually over the course of treatment, followed by a parallel decrease in serum iron. The skin eventually returns to normal. After remission, further phlebotomy is necessary only if the disease relapses.
Low doses of chloroquine and hydrochloroquine (100 to 125 mg orally twice a week) help remove excess porphyrins from the liver by increasing excretion. High doses may cause transient liver damage and worsening of the porphyria. When remission is achieved, therapy is stopped.
The use of chloroquine and hydrochloroquine is not effective in cases of severe renal pathology. Phlebotomy is usually contraindicated in this case, since secondary anemia develops. However, recombinant erythropoietin mobilizes excess iron, reduces the severity of anemia, which is sufficient to still use phlebotomy as a treatment method.
Patients should avoid sun exposure; try to select hats and clothing with better sun protection properties and use zinc or titanium (titanium oxide) sunscreens. Conventional screens that block only UV rays are ineffective, but UV-absorbing protective screens containing dibenzylmethane can help protect patients to some extent. Alcohol should be strictly avoided, but estrogen therapy can be successfully resumed after the disease has remitted.