Definition of Porphyria:

Porphyrias are a rare group of disorders passed down through families in which an important part of hemoglobin, called heme, does not develop properly. Heme is also found in myoglobin, a protein found in certain muscles.

Causes, incidence, and risk factors:

Normally, the body breaks down chemicals, called porphyrins, into heme. The porphyrins leave the body through urine or stools. But persons with porphyria have a genetic defect that interrupts this process. As a result, porphyrins build up in the body. This can lead to rashes, light sensitivity, abdominal pain, and other symptoms.

There are many different forms of porphyria. The most common type is porphyria cutanea tarda.

Drugs, infection, alcohol, and hormones such as estrogen may trigger attacks of certain types of porphyria.