Italian doctors have been baffled by the case of a 21-year-old woman who sweats blood from her face and the palms of her hands.

In the extremely unusual case, the spontaneous bleeding lasts anywhere between one and five minutes. And it can occur at any time, whether during physical activity or even while she is asleep, although she said it is worse when she is stressed.

The blood appears despite the woman not having any skin lesions or obvious triggers for the bleeding, the Canadian Medical Journal reports. 

According to the report, the woman has been suffering the condition for three years and the doctors treating her in Florence are sure she is not faking it.

They have diagnosed her with an extremely rare condition called hematohidrosis, which affects only around one in 10 million people.

Doctors have been able to alleviate some, but not all, of her symptoms by treating her with propranolol, a beta-blocker treatment.

Despite the rarity of the condition, there have been some notable records of it down through history. In one reference, Leonardo Da Vinci told of a soldier who had sweated blood prior to going into battle. 

But perhaps the most famous is Jesus Christ, who is recorded in the Bible as having sweated blood while praying in Gethsemane prior to his crucifixion.

Interestingly, it is only the Gospel of Luke that records the sweating of the blood, perhaps because he was a physician and more interested in the medical aspects of Jesus's suffering than the other Gospel recorders.

Dr. Frederick Zugibe, chief medical examiner of Rockland County, New York, explained that it was possible for blood to enter the sweat glands during times of great stress as the glands are surrounded by 'multiple blood vessels in a net-like form.'