Porphyria is a group of rare disorders that occur when the body has problems making heme, which is a part of hemoglobin, the protein in red blood cells that carries oxygen from the lungs to all parts of the body. Heme also plays a role in clearing drugs and hormones from the body. Porphyria occurs when the body cannot convert compounds called porphyrins into heme, leading to a buildup of natural chemicals called porphyrins in the body. Depending on the type of porphyria, porphyrins or porphyrin precursors may build up in the liver or the bone marrow. Porphyria can affect the skin, nervous system, gastrointestinal system, or all of these, depending on the specific type.

Porphyria can be inherited from one or both parents, or it can be acquired due to environmental factors. Most types of porphyria are caused by gene mutations, and some types of porphyria result from inheriting two gene mutations, one from each parent. However, inheriting a gene or genes that can cause porphyria does not necessarily mean that a person will have symptoms. Environmental factors that can trigger symptoms in porphyria include exposure to sunlight, certain medications, recreational or illicit drugs, dieting or fasting, and smoking.

Symptoms of porphyria can vary depending on the type of porphyria, but they can include abdominal pain, vomiting, constipation, diarrhea, muscle pain, weakness, numbness, tingling, seizures, and skin sensitivity to sunlight. Treatment for porphyria depends on the type and severity of the disorder, but it may include medication, lifestyle changes, and avoiding triggers. For example, treatment for acute porphyria may involve pain medication, addressing the underlying cause, medication called hematin, which is a type of heme the body can use, intravenous fluids and glucose, and admission to the hospital. For people living with cutaneous porphyrias, avoiding sunlight is key to recovery, and some people benefit from therapeutic phlebotomy (blood draw) to reduce the amount of iron in the liver.