Patient education: Porphyria cutanea tarda (The Basics)

What is porphyria? — Porphyria is a condition that affects how the body makes something called "heme." Heme is made from iron and helps blood cells carry oxygen around the body. In people with porphyria, chemicals can build up in the body and cause symptoms.

There are several different kinds of porphyria. "Cutaneous" porphyrias cause skin symptoms. "Acute" porphyrias cause symptoms like belly pain and changes in brain functioning, mood, or thinking.

Porphyria cutanea tarda ("PCT") is the most common porphyria that affects the skin. In PCT, porphyrins build up in the skin.

Unlike the other kinds of porphyria, most cases of PCT are not caused by a change in a gene. In most people, PCT is caused by something that affects how the body handles iron. Examples are liver disease, certain infections, hormones, smoking, and alcohol use.

Sometimes, people have a gene that makes them absorb more iron. This gene is called HFE, and the condition it causes is called "hereditary hemochromatosis."

What are the symptoms of PCT? — The main symptom is blistering of the skin when it is exposed to sunlight. The blisters usually form a little while after exposure, so it's not always obvious that sun was the cause. The blisters most commonly form on areas that get a lot of sun, like the face, neck, ears, backs of the hands, and feet. The skin might be painful or itchy, and blisters often lead to scarring over time. Blistered skin is usually very fragile and can break or tear easily.

Sometimes, the hair falls out where the blisters form. Sometimes, people with PCT grow extra hair on other parts of the body, especially the cheeks or forearms.

Will I need tests? — Yes. The first test is usually a test that measures the amount of porphyrins in your body. It can be done on either blood or urine. If this test is positive, you will get more tests of your blood, urine, and, possibly, a sample of bowel movement.

Once your doctor has confirmed PCT, they will likely order other tests, too. These include:

●Blood tests, including tests to measure iron level and check for liver disease

●Tests to check for infection – Certain infections, including hepatitis C and HIV infection, seem to increase a person's risk of PCT.

●Genetic testing – This can show if you carry a porphyria gene. It can also check if you have a gene that causes your body to absorb extra iron.

How is PCT treated? — In people with skin blisters caused by PCT, treatment options include:

●Avoiding sun – This is most important before other treatments are used. If you need to be outside, use protection like hats, gloves, sunglasses, and sunscreen.

●Having blood removed – Doctors call this "phlebotomy." It's done the same way as donating blood. This treatment is used if you have a lot of extra iron in your body. The number of treatments depends on how much extra iron you have. Some blood centers let you donate this blood for people who need a transfusion, while others do not.

●Medicine – Some people get a medicine called hydroxychloroquine (brand name: Plaquenil) or chloroquine. It comes as a pill that you take twice a week, usually for at least a few months. It is generally less expensive than the treatments to have blood removed. It is not usually used in people with liver damage. Also, if you take this medicine, you will need to get an eye exam before and after treatment. That's because, in rare cases, it can lead to vision problems. These medicines can also cause abnormal heart rhythms in some people.

●Avoiding things that could increase symptoms – For example, you should avoid alcohol, smoking, iron supplements, and medicines containing the hormone estrogen. If you have hepatitis C or HIV, your doctor will talk to you about treating that, too.

After getting treatment for PCT, you will continue to see your doctor for tests, probably 1 or 2 times a year. If tests show that your porphyrin or iron levels are high, you can begin treatment again. Most people who follow their treatment plan do not get more symptoms, and they can live a normal life.

What if I want to have children? — For most people, PCT is not caused by a gene that runs in families. But about 1 in 5 people do have a porphyria gene that could be passed on to a child. If this happens, it increases the child's chance of having PCT when they get older.

If you have children, they might choose to talk to their doctor or a genetic counselor. This can help them decide if they should be tested for the gene when they are older.

More on this topic

Patient education: Porphyrias (The Basics)
Patient education: Hepatitis C (The Basics)
Patient education: HIV/AIDS (The Basics)
Patient education: Nonalcoholic fatty liver disease (The Basics)
Patient education: Cirrhosis (The Basics)
Patient education: Hemochromatosis (The Basics)