Porphyria Cutanea Tarda Information

Porphyria cutanea tarda (PCT) is the most common porphyria and causes blistering of skin exposed to sunlight. The disorder results from low levels of the enzyme responsible for the fifth step in heme production. Porphyria cutanea tarda occurs throughout the world. PCT occurs in persons of all ethnic groups. Some people are born with the condition, but in the majority it appears later in life, having been caused by a toxin (such as some pesticides and fungicides) affecting the liver. Other contributing factors can be the intake of alcohol, iron supplements and oestrogen-containing medicines. Infection with the human immunodeficiency virus (HIV) is a less common precipitating factor. These factors are thought to interact with iron and oxygen in the liver and thereby inhibit or damage the enzyme uroporphyrinogen decarboxylase. When signs and symptoms occur, they usually begin in adulthood and result from the skin becoming overly sensitive to sunlight. Areas of skin exposed to the sun develop severe blistering, scarring, changes in pigmentation, and increased hair growth. The disorder can be acquired or can be caused by an inherited gene mutation in the UROD gene. The inherited form of PCT is also called familial PCT and follows autosomal dominant inheritance. Exposure to light, oxygen, minor bumps and scrapes leads to the chronic skin rash.

In about 80% of people with porphyria cutanea tarda, the disorder does not appear to be hereditary and is called sporadic. Pregnancy may also trigger an attack as hormone levels change, while some women have regular attacks prior to their periods. People with porphyria cutanea tarda also have increased iron levels in the liver. It is usually necessary for an environmental trigger to be present to cause symptoms of either the acquired or inherited type of PCT. For patients with porphyria cutanea tarda who are anemic due to other chronic diseases (eg, renal failure, human immunodeficiency viral infection), human recombinant erythropoietin can be used to stimulate erythropoiesis. To diagnose porphyria cutanea tarda, a doctor tests the blood plasma, urine, and stool for increased levels of porphyrins. Anyone with PCT should not take any medicine without discussing it with their doctor. Porphyria cutanea tarda is the most readily treated porphyria. Avoiding alcohol and other precipitating factors is beneficial.

Causes of Porphyria cutanea tarda

The common causes and risk factor's of Porphyria cutanea tarda include the following:

• A defective enzyme in the liver (uroporphyrinogen decarboxylase).
• Heavy alcohol use.
• Excess iron in body tissues.
• Polychlorinated aromatic hydrocarbons.
• Infection with hepatitis C virus.
• Smoking.

Symptoms of Porphyria cutanea tarda

Some sign and symptoms related to Porphyria cutanea tarda are as follows:

• Vomiting.
• Increased sensitivity to the sun.
• Red urine.
• Fluid filled blisters (vesicles and bullae).
• Numbness or tingling.
• Muscle weakness or paralysis.
• Crampy abdominal pain (may be extremely severe).

Treatment of Porphyria cutanea tarda

Here is list of the methods for treating Porphyria cutanea tarda:

• Porphyria cutanea tarda is the most readily treated porphyria. A procedure called phlebotomy, in which a pint of blood is removed, is the most widely recommended treatment.
• Antimalarial tablets i.e low-dose chloroquine or hydroxychloroquine may be recommended, but must be used cautiously. This medication makes the porphyrins more soluble so more are excreted in the urine.
• Avoid alcohol, oestrogen, and iron.
• For women taking estrogen, doctors discontinue the estrogen therapy (because it is a precipitating factor of the porphyria) until phlebotomy has been completed and porphyrin levels are normal.
• Use tanning cream containing dihydroxyacetone : this can block the responsible light to some extent.