Porphyria is the name given to a group of rare disorders in which there are deficiencies of enzymes required to make the substance heme. Heme is a red-colored pigment manufactured in the liver and bone marrow which forms part of hemoglobin in red blood cells. Porphyrias may affect the skin, the nervous system, or both. The symptoms of porphyria affecting the skin develop in response to sunlight and can include itching, blistering, and swelling. When porphyria affects the nervous system, psychiatric symptoms may occur, as well as abdominal pain, nausea and vomiting, and muscle weakness or paralysis.
Although one type of porphyria, known as porphyria cutanea tarda, tends to be acquired, in most cases these diseases are inherited disorders, with genes being passed on from other family members. In each distinctive type of porphyria, there is a deficiency of a different one of the eight enzymes used in the process of making heme. A deficiency in the heme manufacturing path leads to a buildup of substances used in the manufacturing process and, as these substances accumulate in the body, the symptoms of porphyria develop.
Porphyria cutanea tarda is the type of porphyria which occurs most frequently, typically in men over the age of 50. It may develop as the result of alcohol abuse, chemical exposure, or in association with the use of certain drugs, such as contraceptives. Symptoms of porphyria cutanea tarda occur when skin is exposed to sunlight. The skin becomes red and itchy and large blisters may develop, together with abnormal hair growth and skin pigmentation. There may be an excess of iron in the body and liver damage could occur.
Acute intermittent porphyria is the most common porphyria affecting the nervous system. Here, symptoms of porphyria are extremely variable, and some people have no symptoms at all. A severe attack may begin with restlessness and progress to pain in the abdomen, possibly with constipation and vomiting. The urine may appear red or dark, due to the removal of accumulated substances which are part of the heme manufacturing process.
Psychiatric problems such as hallucinations, depression or mania can also be symptoms of acute intermittent porphyria. Various muscles may become weak, or even paralyzed, and, in extreme cases, it could be difficult to breathe. Tingling or numbness of limbs could develop and a person may have seizures or become confused. Death could occur suddenly due to an irregular heart rhythm.
Management of porphyria varies according to the type and the severity of an attack. Known causes are avoided if possible, and the symptoms of porphyria are sometimes treated using medication, or by giving heme into a vein. Serious episodes are usually managed in the hospital, and in some cases bone marrow or liver transplants may be carried out.