Porphyria is a group of different disorders caused by abnormalities in the chemical steps leading to the production of heme, a substance that is important in the body. The largest amounts of heme are in the blood and bone marrow, where it carries oxygen. Heme is also found in the liver and other tissues. Porphyria is also known as the "vampire disease"
Some modern scholars have argued that vampire stories may have been influenced by the rare illness called porphyria. Porphyria was thought to be more common than elsewhere in small Transylvanian villages (roughly 1000 years ago) where inbreeding probably occurred. The haem group, found in every blood cell in the human body, is excited by electrons, but in a controlled fashion. However, the haem groups in porphyria sufferers causes uncontrollable tissue, bone and skin damage, made worse when the person comes into contact with sunlight. This would have given the porphyria sufferer a very pallid skin colour, with teeth that appear larger than normal, due to the porphyria damaging the gum tissue and causing it to recede. These people would have been very anemic, and drinking (animal) blood was a traditional treatment for anemia. Certain forms of porphyria are also associated with neurological symptoms, which can create psychiatric disorders. However, suggestions that porphyria sufferers crave the heme in human blood, or that the consumption of blood might ease the symptoms of porphyria, are based on a severe misunderstanding of the disease.
He seems to break out in blisters when exposed to sunlight he may have porphyria.