What is porphyria?

The term porphyria describes a group of eight disorders that affect the skin and nervous system. Most of these disorders are inherited (passed down from family members). One type of porphyria, porphyria cutanea tarda (PCT), isn’t always inherited.

How common is porphyria?

Porphyria is rare. Doctors don’t know the exact number of people living with this condition, because many have no symptoms of the disease. However, it has been estimated that all forms of porphyria combined affect fewer than 200,000 people in the United States.

What causes porphyria?

Each type of porphyria is caused by low levels of a specific enzyme (a specific enzyme [chemical] for each type of porphyria) that is needed during the making of heme. Heme is an iron-containing pigment that is vital for all the body’s organs. Heme is part of the hemoglobin in your blood. Hemoglobin carries oxygen to body tissues and gives red blood cells their color. Heme is also part of proteins in the liver that help the liver function properly.

In the several-step process of making heme, several other compounds – called porphyrins and porphyrin precursors – are created. If there is a low level of any one of the enzymes needed to make heme, these porphyrin and porphyrin precursors build up in the liver, skin, and other body tissues. When they build up, people may develop symptoms of one of the types of porphyria.

What are the types of porphyria?

The specific names of the eight types of porphyrias are:

  • Delta-aminolevulinate-dehydratase deficiency porphyria
  • Acute intermittent porphyria
  • Hereditary coproporphyria
  • Variegate porphyria
  • Congenital erythropoietic porphyria
  • Porphyria cutanea tarda
  • Hepatoerythropoitic porphyria
  • Erythropoietic protoporphyria

Doctors classify porphyrias in several different ways. Besides defining by each specific type, doctors also classify porphyria in two broad categories:

  • Acute porphyrias - Onset is rapid. Symptoms last a short time, but they may come back from time to time. Most often, acute porphyrias affect the nervous system.
  • Cutaneous porphyrias - Only the skin is affected.

Doctors also classify porphyria by which body system becomes overactive:

  • Erythropoietic porphyrias - The bone marrow produces porphyrins in higher levels than normal.
  • Hepatic porphyrias - The liver makes too many porphyrins and porphyrin precursors.

What are the symptoms of porphyria?

The symptoms of porphyria vary depending on type. Symptoms range from mild to severe. Some people with porphyria have no symptoms. In some cases, symptoms can be life-threatening unless treated.

People living with cutaneous types of porphyria, which affects the skin, often experience symptoms including:

  • Oversensitivity to sunlight
  • Itching
  • Swelling of skin exposed to sunlight
  • Abrasions, blisters on the skin, skin erosions
  • Scarring of sun exposed areas of the skin leading to fragile skin

Acute porphyrias can cause symptoms that affect the nervous system. These symptoms generally occur suddenly and usually last a short period of time. Symptoms of acute porphyrias include:

  • Pain in the abdomen, chest, arms, legs, or back
  • Nausea or vomiting
  • Constipation (difficulty passing stool)
  • Urinary retention (inability to empty bladder completely)
  • Mental status changes, including confusion and hallucinations
  • Seizures
  • Muscle weakness

Who is most at risk for getting porphyria?

Porphyria most often results from genetic mutations passed down from parent to child. You are more at risk for porphyria if a parent has the disorder.

Unlike the other types of porphyrias, porphyria cutanea tarda (PCT) occurs when an inactive acquired disease, like hepatitis C or human immunodeficiency virus (HIV), becomes active in the body. The disease’s activity causes a deficiency in the enzymes needed to produce heme. Factors that can trigger PCT include:

Symptoms of other types of porphyria can be triggered by:

  • Smoking
  • Exposure to sunlight
  • Stress
  • Dieting/fasting
  • Using estrogen
  • Drugs, including barbiturates, tranquilizers, birth control pills, and sedatives

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