An original reason of a werewolf and vampire myths was suggested by David Dolphin.
He was a biochemist and for the first time published this theory in 1985. In this theory
porphyria is suggested as an explanation for such myths. It sounds logically because
there are many similarities in porphyria symptoms and the folklore descriptions of
vampires. David Dolphin assumption gave a life to an urban legend, where assocation
between vampires and porphyria is accepted as a fact.
Porphyria cutanea tarda is a disease, which lead to an hyper sensitivity of skin to a sunlight. Exposing areas of skin to light can cause an abnormal hair growth, scarring and disfigurements. As an additional prove of this theory spoke the fact, that the missing heme of a porphyria victims should be restored through the stomach. These thoughts correlate to the legends about vampires drinking human blood.