It was probably one of the most bizarre medical cases a team of Italian doctors had ever seen.

A 21-year-old woman was admitted to hospital with a condition that caused her to sweat blood from her face and from the palms of her hands. This despite no sign of any skin lesions.

The case was highlighted Monday in the Canadian Medical Association Journal (CMAJ).

Doctors say the patient had a three-year history of bleeding. There was no obvious trigger, and the spontaneous bleeding could happen while she slept and during physical activity. More intense bleeding happened when the patient was under stress, with episodes lasting anywhere between one and five minutes.

Dr. Roberto Maglie, a dermatologist at the University of Florence and co-author of the article, told CBC News in an email that he could not discuss any details about the patient due to confidentiality.

Doctors could find no obvious trigger for the bleeding, and said tests showed the 21-year-old patient had normal blood count and blood-clotting functions. (CMAJ)

The article states that the unidentified patient had become socially isolated because of the bleeding and that she had developed depression. After tests revealed her blood count and blood-clotting functions were normal, doctors ruled out "factitious disorder"— she wasn't faking it.

Doctors instead diagnosed her with hematohidrosis, a rare disease that causes a patient to excrete or sweat blood through unbroken skin or pores. Bleeding has also reportedly occurred in areas of the body without sweat glands.

Doctors in this case also say literature does not provide a single explanation for the source of bleeding. But various causes have been proposed. It could be a bleeding disorder where the blood's ability to clot is impaired or a psychogenetic disease, where an extreme or exaggerated emotional response provokes a physical illness.

'Most unusual'

A Toronto hematologist says the case is "most unusual."

"I can say with clarity that I've never seen a case like this — ever," said Dr. Michelle Sholzberg, co-director of the Hemophilia Comprehensive Care program at St. Michael's Hospital. "And I can say that I've seen some of the worst bleeding disorders, and I've never seen them sweat blood."

I can say with clarity that I've never seen a case like this — ever. - Dr. Michelle Sholzberg

Sholzberg doesn't think the patient has a bleeding disorder. "I think this person has a very bizarre anatomical defect on a microscopic level that is resulting in this very unusual symptom," she said. Sholzberg says the abnormality could be in the sweat ducts themselves.

Canadian medical historian Jacalyn Duffin says at first she was skeptical whether people could sweat blood. She thought the Italian doctors were being duped. But after an exhaustive review of historical literature and more recent reports on cases of hematohidrosis, or sweating blood, she's a believer.

"After all the research that I've done, I am convinced of the plausibility and the possibility that it exists," she said. Duffin, who is also a hematologist, wrote a commentary that accompanies the journal article.

She acknowledges that hematohidrosis syndrome is incredibly rare. The medical history has been "muddled" with references in religious literature to the crucifixion of Christ, she says and the two are very difficult to separate.

"But case reports start appearing in the 16th century, and quite distinct from anything to do with the crucifixion, or Christianity", she says. "There are mentions of the phenomenon as far back as Aristotle ... prior to the time of Jesus," she told CBC News from her home in Kingston, Ont.

After reviewing literature on hematohidrosis dating back to the time of Greek philosopher Aristotle, Canadian medical historian Jacalyn Duffin says she's convinced the disorder exists. (Kas Roussy/CBC)

She found one case in the early 1600s of a 12-year-old Swiss boy with a high fever who sweated blood through his shirt. And then a case of a young Belgian condemned to death who was so distressed, he sweated blood.

Duffin says she was surprised to discover how many modern cases there were — at least 18 of them since 2000. "A significant proportion of all the actual cases I could find have emerged in recent decades," she said, but she can't explain why.

"The very fact that there are sporadic references to the phenomenon through time, scattered in many different places, tends to suggest to me that it must occur." Hematohidrosis is not fatal, but Duffin says it is terrifying for patients who have to go through it.

As for the patient in Italy, doctors treated her with propranolol, a heart and blood pressure medication. It led to a marked reduction but not a complete remission of her bleeding.