Types of Porphyrias
The most common classification of Porphyrias is based on the region of the body where there is an excessive production and accumulation of porphyrins and on the types of symptoms that are caused; based on this classification, Porphyrias are divided into acute (or hepatic) porphyrias and cutaneous porphyrias.
Acute porphyrias occur mostly when porphyrins accumulate in the liver. Patients affected by acute porphyria experience muscle pain, pain in the abdominal area and vomiting. This type of porphyria also has several other implications at a neurological level, however, as patients may suffer from hallucinations, paranoia, depression and anxiety. These types of porphyrias are also called acute because the episodes during which the signs and symptoms occur appear quickly and do not usually last long. Types of acute porphyrias are acute intermittent porphyria and erythropoietic porphyria.
Cutaneous porphyrias, instead, mainly target the skin, making it more sensitive to exposure to light (increased photosensitivity). Those affected by cutaneous porphyrias suffer from blisters, erythema, and even necrosis of the skin when they are exposed to sunlight. This type of porphyria has been one of the main sources of inspiration for the legends of vampires, who are described as supposedly non-human creatures that are deathly “allergic" to sunlight. Some types of porphyrias belonging to this category are porphyria cutanea tarda and hepatoerythropioetic porphyria.
Even rarer are neurocutaneous porphyrias, which are conditions that affect both the skin and the nervous system, where neurological episodes are triggered by exposure to sunlight. Types of neurocutaneous porphyrias are variegate porphyria and hereditary coproporphyria.