This group of disorders results from a buildup of natural chemicals in the body that affect the nervous system and skin. Learn how to avoid symptom triggers.
Porphyria (por-FEAR-e-uh) refers to a group of rare disorders that result from a buildup of natural chemicals called porphyrins in the body. Porphyrins are needed to make heme, a part of hemoglobin. Hemoglobin is a protein in red blood cells. It carries oxygen to the body's organs and tissues.
Eight enzymes are needed to change porphyrins into heme. Without enough of any of these enzymes, porphyrins build up in the body. High levels of porphyrins can cause major problems, mainly in the nervous system and skin.
There are two general types of porphyrias. Acute porphyrias start rapidly and mainly affect the nervous system. Cutaneous porphyrias mainly affect the skin. A few types of porphyrias affect both the nervous system and the skin.
Symptoms of porphyria vary, depending on the specific type of porphyria and how severe it is. Porphyria is usually inherited. One or both parents pass along a changed gene to their child.
Although porphyria can't be cured, medicines and certain lifestyle changes may help you manage it. Treatment for symptoms depends on the type of porphyria you have.
Symptoms can vary widely by type of porphyria and in how severe the symptoms are. Symptoms also can vary among people with the condition. Some people with a gene change that causes porphyria never have any symptoms.
Acute porphyrias include forms of the disease that usually cause nervous system symptoms. A few forms also can affect the skin. Symptoms appear quickly and can be severe. Symptoms may last hours, days or weeks.
The most common form of acute porphyria is called acute intermittent porphyria (AIP). AIP may last hours or days. Intermittent means that the symptoms may go away but return later. When the symptoms occur they are sometimes called attacks.
Symptoms of acute porphyrias may include:
Cutaneous porphyrias include forms of the disease that cause skin symptoms as a result of sensitivity to sunlight. These forms usually don't affect the nervous system. Porphyria cutanea tarda (PCT) is the most common type of all the porphyrias.
Sun exposure may cause:
Erythropoietic protoporphyria (uh-rith-roe-poi-ET-ik pro-toe-por-FEAR-e-uh), also called EPP, is a rare type of cutaneous porphyria. It's the most common childhood porphyria. Sun or artificial light exposure quickly results in painful skin burning, irritation and swelling. Small bumps and blisters also appear. Repeated exposures can cause thick, leathery skin and scarring.
Many symptoms of porphyria are like those of other, more common conditions. This can make it difficult to know if you're having an attack of porphyria. If you have symptoms that could be porphyria, get medical attention. Prompt treatment is important.
All types of porphyria involve a problem making heme. Heme is a part of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen from the lungs to all parts of the body. Heme also plays a role in clearing drugs and hormones from the body.
Heme is made in the bone marrow and liver. This process involves eight different enzymes that turn porphyrins into heme. A shortage or change in any of these enzymes causes a buildup of porphyrins. Which enzyme is affected determines the type of porphyria.
In cutaneous porphyrias, porphyrins build up in the skin. When exposed to sunlight, they cause symptoms. In acute porphyrias, the buildup affects the nervous system, causing symptoms.
Most forms of porphyria are caused by a gene change passed down from one or both parents. Porphyria can occur if you inherit:
Just because you inherit a gene or genes that can cause porphyria doesn't mean that you'll have symptoms. You might never have symptoms. This also is the case for most carriers of the changed genes.
Porphyria cutanea tarda (PCT) usually is not passed down in families. In PCT, certain triggers can cause a buildup of porphyrins that may cause symptoms. Examples of triggers include:
In an autosomal dominant disorder, the changed gene, also called a mutation, is a dominant gene. It's located on one of the nonsex chromosomes, called autosomes. You need only one changed gene to be affected by this type of disorder. A person with an autosomal dominant disorder — in this example, the father — has a 50% chance of having an affected child with one changed gene. The person has a 50% chance of having an unaffected child.
In addition to genetic risk factors, environmental risk factors may trigger symptoms in porphyria. When exposed to the trigger, the body's demand for heme production increases. This overwhelms the low level of a needed enzyme, setting in motion a process that causes a buildup of porphyrins.
Examples of triggers include:
Possible complications depend on the form of porphyria:
In rare cases, a bone marrow transplant or liver transplant may be needed.
Although there's no way to prevent porphyria, if you have the condition, avoid triggers to help prevent symptoms.
Because porphyria is usually an inherited disorder, your siblings and other family members may want to consider genetic testing to determine if they have the condition. Genetic counseling is important to help understand test results and risks.
Many symptoms of porphyria are like those of other more common diseases. Because porphyria is rare, it can be difficult to diagnose.
Lab tests are needed to make a diagnosis of porphyria and to determine which form of the condition you have. The types of tests depend on the type of porphyria your health care provider suspects. Tests include a combination of blood, urine or stool testing to measure porphyrin levels. Other tests may be needed. Genetic tests may be helpful to confirm the diagnosis and determine the type of porphyria you have.
Talking with a genetic counselor can give you information about genetic tests and the risk of porphyria for your children. If you have porphyria, genetic testing and counseling also may be recommended for family members.
Treatment depends on the type of porphyria you have and how severe your symptoms are. Treatment includes medicine. It also includes identifying and avoiding symptom triggers, and relieving symptoms when they occur.
To avoid triggers:
Treatment of acute porphyria attacks focuses on providing fast treatment of symptoms and preventing complications. Treatment may include:
Givosiran (Givlaari) is a monthly shot for adults with acute hepatic porphyria. In hepatic porphyrias, which include acute intermittent porphyria, the lack of the enzymes needed to make heme occurs in the liver. Givosiran can reduce the number of porphyria attacks. Discuss safety information and potential serious side effects with your health care provider.
Treatment of cutaneous porphyrias focuses on reducing exposure to triggers such as sunlight. It also includes reducing the amount of porphyrins in the body to help relieve symptoms. Reducing porphyrins may include:
High doses of beta carotene are a common treatment for erythropoietic protoporphyria.
A treatment option only approved for erythropoietic protoporphyria is afamelanotide (Scenesse), a medicine that increases melanin in the skin. This protects skin from sunlight and allows more time in the sun without a painful skin reaction. An implant is placed under the skin that slowly releases the medicine. Talk with your health care provider about safety information and any potential serious side effects.
If you have porphyria:
If you have symptoms of porphyria, you're likely to start by seeing your primary care provider. However, because porphyria can be difficult to diagnose, you may be referred to a specialist in blood disorders (hematologist) or skin conditions (dermatologist).
Here's some information to help you get ready, and what to expect during your appointment.
Before your appointment, make a list of:
Questions to ask may include:
Feel free to ask other questions during your appointment.
Your health care provider is likely to ask you several questions. These may include:
Be ready to answer questions so that you can spend time on areas that are important to you.