Porphyrias: Causes, Symptoms, and Types
Porphyrias are a rare group of disorders caused by lack of the enzymes necessary for production
of heme. Heme is a chemical compound that makes blood red, and it also contains iron. Heme is
a part of hemogloblin, the protein that allows red blood cells to carry oxygen from the lungs to
all other parts of the body. Heme is also a component of liver cytochromes, the protein
responsible for processing chemicals in order to remove them from the body. Heme also is found
in myoglobin, a protein found in muscle.
The lack of enzymes that produce heme causes heme precursors, porphyrins, to accumulate in
bone marrow and the liver, flood into the blood, or become excreted in urine or stool.
Causes of porphyrias
Most porphyrias are hereditary. Drugs, infection, alcohol, and hormones may trigger porphyria
attacks.
Symptoms of porphyrias
The following are symptoms of porphyrias:
 Photosensitivity—occurs because some porphyrins are deposited in the skin and generate a
charged, unstable form of oxygen, which leads to skin damage when skin is exposed to light
and oxygen
 Nerve damage, which may lead to pain or paralysis
 Abdominal pain and liver damage
 Red or brown urine sometimes following an attack
 Anxiety and delirium
 Muscle pain
 Muscle weakness or paralysis
 Numbness or tingling
 Back, arm, and leg pain
 Tachycardia
 Loss of deep tendon reflexes
 Severe electrolyte imbalances, low blood pressure, and shock following acute attacks—
sometimes life threatening
 Seizures, which are not treatable with phenytoin or barbiturates, because both of these drugs
precipitate a porphyric attack
Types of porphyrias
Seven different types of porphyrias exist, but the following three are the most common.
Porphyria cutanea tarda
This is the only porphyria that can occur in someone without an inherited enzyme deficiency,
with only 20% of cases shown as hereditary. Porphyrins accumulate in the liver and then travel
to the skin, causing skin damage.
Causes of porphyria cutanea tarda include:
 Excess iron in body tissues
 Alcohol usage
 Estrogen usage
 Hepatitis C
 Human immunodeficiency virus (HIV)
 Possibly smoking
Symptoms include:
 Blistering of sun-exposed areas, with crusting and scarring
 Hair growth on sun-exposed parts of the body
 Liver damage, including cirrhosis and liver cancer
Treatment is usually phlebotomy to remove excess iron. Chloroquine or hydroxychloroquine
remove the excess porphyrins from the liver.
Acute intermittent porphyria
Acute intermittent porphyria is most common in people from northern Europe and more common
in women. Acute onset of neurological symptoms is usually the first sign. Most people with this
enzyme deficiency never have symptoms, but an attack can occur following something as simple
as a change in diet or medication. Even psychological stress can precipitate an attack.
Symptoms include:
 Abdominal pain
 Nausea
 Vomiting
 Constipation
 Diarrhea
 Difficulty passing urine
 Rapid heart rate
 High blood pressure
 Sweating
 Restlessness
High blood pressure may remain after the attack has ended. Damage may occur to nerves that
control muscles, leading to weakness, usually beginning in the shoulders and arms. Eventually
muscle weakness may affect breathing, which can lead to tremors and seizures. Attacks are
rarely fatal, but may cause permanent disability.
Treatment of severe attacks may include intravenous heme, intravenous glucose, or a highcarbohydrate diet (especially for those whose attacks were brought on by a low-calorie or lowcarbohydrate diet), sleep aids, phenothiazine for the gastrointestinal symptoms and anxiety, betablockers, and pain medication. A catheter sometimes is used to drain the bladder.
Erythropoietic protoporphyria
Erythropoietic protoporphyria occurs most often in white people, and equally in men and
women. The heme precursor protoporphyrin accumulates in bone marrow, red blood cells, blood
plasma, skin, and the liver. Extreme sensitivity to sunlight results from the accumulation of the
enzyme in the skin. Liver damage results from the buildup of the enzyme in the liver.
Accumulation of the enzyme in the bile may lead to bile stones.
The skin is painful and swollen after exposure to the sun, although it does not usually blister or
scar. Liver damage may result in jaundice and spleen enlargement. Beta-carotene makes some
people more tolerant of the sun, although it still is necessary to avoid exposure to the sun.
Surgical removal of the gallstones sometimes is necessary. Liver transplant is sometimes
necessary in severe cases.
Dietary advice
The following dietary advice is suggested for people with porphyrias:
 Ingest a high-carbohydrate diet, with 55% to 60% of the total calories coming from
carbohydrate
 Avoid alcohol
 Avoid iron supplements
References and recommended readings
Mayo Clinic staff. Porphyria. Mayo Clinic Web site.
http://www.mayoclinic.com/health/porphyria/DS00955. Published May 7, 2011. Accessed April
7, 2014.
MedlinePlus. Porphyria. US National Library of Medicine, National Institutes of Health.
www.nlm.nih.gov/medlineplus/ency/article/001208.htm. Updated February 28, 2011. Accessed
April 7, 2014.
Review Date 4/14
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