Porphyrins are pigments made by the liver and other tissues. They are involved in the formation of many important substances in the body, such as hemoglobin, which carries oxygen in the blood.
Many genes are involved in the production of porphyrins. If one of these genes is mutated, hepatic porphyria may occur, resulting in an abnormal increase of pigments in the body. There are two types of porphyria: cutaneous and acute.
Genetic porphyria often is “silent,” meaning that the genetic change causes symptoms only in the presence of certain environmental triggers, such as alcohol consumption, inadequate diet and certain medications — especially sedatives related to barbiturates, anti-seizure drugs and oral contraceptives. It can also present after the individual contracts heavy metal poisoning and certain anemias. Excess iron and estrogen play a role in some patients, and there also is a frequent association with hepatitis C liver disease.
Symptoms vary depending on the type of porphyria, but some of the more common include:
- Dark urine
- Skin sensitivity, including blistering, of areas exposed to the light, such as the face and back of hands
- Pain in the abdomen
Treatment for hepatic porphyria depends on the type. However, for both cutaneous and acute porphyria, the first step of therapy involves identifying and eliminating the trigger factors, such as alcohol, certain medication or excess iron.
For patients with cutaneous porphyria whose iron levels are high, iron depletion is recommended. This involves removing the excess iron from the body by bloodletting, usually drawing a pint at a time in regular intervals. This is done in the same way that blood is drawn from donors at blood banks. When the body replenishes the blood, it draws iron from storage sites such as the liver. Repeated over time, this process eventually eliminates the excess iron and leads to reduced porphyrin levels and improved sun tolerance.