Dark Friday: Medical Explanations for Vampirism

A rare disease called porphyria (also called the "vampire" or "Dracula" disease) causes vampire-like symptoms, such as an extreme sensitivity to sunlight and sometimes hairiness. In extreme cases, teeth might be stained reddish brown, and eventually the patient may go mad.

Documented medical disorders that people accused of being a vampire may have suffered from include haematodipsia, which is a sexual thirst for blood, and hemeralopia or day blindness. Anemia (“bloodlessness”) was often mistaken for a symptom of a vampire attack.