Porphyria is an inherited disease in which an important part of the hemoglobin and myoglobin, called heme, is not made correctly. Porphyrins are made during the multi-step process to create heme. However, people with porphyria have a deficiency of enzymes needed for the process. This deficiency causes abnormal amounts of porphyrins and other related chemicals to build up in the body. Symptoms of this build-up can affect the skin or the nervous system by manifesting as photosensitivity, causing skin rashes, seizures, nerve damage, and abdominal pain. Many of the symptoms are very similar to other disorders, which makes diagnosing porphyria difficult at times. Find out more about the various types of porphyrias, tests, and treatments.