Porphyria

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
• Hepatoerythropoietic 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:

• Smoking
• Drinking alcohol
• HIV
• Chronic hepatitis C
• High iron levels in the body
• Medications containing estrogens
• Genetic changes resulting from hemochromatosis, a disease causing excessive iron absorption in the body

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

How is porphyria diagnosed?

Diagnosis can be difficult because symptoms of the porphyrias can resemble the symptoms of many other diseases.

If doctors suspect you have porphyria, blood and urine tests screen for porphyrins and other porphyrin precursors. Feces (stool) tests may be necessary to confirm the diagnosis.

Doctors also diagnose porphyria using genetic testing of a blood sample. This type of test is very accurate. Doctors often use it if family members are known to have porphyria.

How is porphyria treated?

Treatment for porphyria depends on the type of porphyria you have and your symptoms.

For people living with cutaneous porphyrias, avoiding sunlight is key to recovery. Your doctor may also recommend that you avoid substances, like alcohol, that trigger symptoms. Some people with cutaneous porphyria benefit from therapeutic phlebotomy (blood draw). This type of blood draw reduces the amount of iron in the liver.

Treatment for acute porphyria involves intravenous (IV) heme or glucose infusions (adding heme or glucose directly into a vein). These therapies decrease the number of porphyrins or porphyrin precursors produced in the liver. Other drugs are under investigation and may be available through clinical trials. Ask your doctor if a clinical trial is something to consider for your specific type of porphyria.

Dietary changes, including eating high amounts of carbohydrates and calorie-rich foods, also help manage symptoms.

Patients with acute porphyria who have severe symptoms or who have other types of porphyria may require more invasive treatments to manage symptoms. Treatment options may include blood transfusions, surgery to remove the spleen, and liver and bone marrow transplantation.

What complications are associated with porphyria?

For some people, erythropoietic porphyria leads to liver failure. If this occurs, a liver transplant can be a life-saving treatment.

Some types of acute porphyrias cause muscle weakness. Muscle problems can be life-threatening if weakness affects the muscles that make respiration (breathing) possible. Hospitalization is required if porphyria affects the respiratory muscles.

Can porphyria be prevented?

Because genetic mutations cause most types of porphyria, the disorder can’t be prevented. However, you can avoid triggers that may cause symptoms. These triggers include smoking, alcohol consumption, and exposure to sunlight. Drugs that may need to be avoided include barbiturates, tranquilizers, birth control pills, and sedatives.

What is the prognosis (outlook) for people with porphyria?

Most people with porphyria recover from their symptoms. Because genetic mutations cause this condition, you may experience symptoms throughout your life.

When should I call my doctor?

If you develop any symptoms of porphyria, or if your symptoms get worse, contact your doctor immediately. They can find the cause of your symptoms and develop a treatment plan tailored to your individual needs.