Porphyria, for example, is a group of disorders that affects the skin and nervous system. Symptoms of that disease include sensitivity to sunlight, insomnia, and skin redness, which might make the skin look bloody. Sound familiar?
“In the 10th or 11th century, Romanians at the time often didn’t bury their dead in very deep graves,” McDonald says. “Sometimes, the bodies would shift. So imagine you’re a peasant, and you come across a body that is pale and looks like it has blood around the mouth. You might think he’d been walking around, feasting on the blood of others.”
While that condition helped fuel the myth of the vampire, McDonald notes that the first appearance of the character Count Dracula occurred in 1897, with the first printing of Bram Stoker’s Dracula.
Another hallmark of Dracula? An uncontrollable temper, which can also be attributed to porphyria. Rage issues can also be linked to another disorder—rabies—which, along with its symptoms of panting and foaming at the mouth, helped give rise to the myth of the Wolfman.
“And of course, hypertrichosis—the excessive growth of unwanted hair—was also a factor,” McDonald adds.
Armed with this knowledge, Dracula and the Wolfman might seem less frightening the next time they appear on screen to stalk their prey. According to McDonald, they’re not fearsome; they’re just not feeling well.