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What Is Hematidrosis?

Meshell Powell
Meshell Powell

Hematidrosis is an extremely rare condition in which a person appears to sweat blood. Although there is no clear scientific evidence concerning this condition, it has been reported to exist for several centuries. The condition has been most commonly reported during extreme bouts of fear or anxiety, such as is often experienced when a person is facing death. A small net-like structure of tiny blood vessels, known as capillaries, surrounds the sweat glands. It is possible for these blood vessels to rupture when a person is faced with an extremely stressful situation, causing blood to exit the body through the sweat glands.

Although there are other potential causes of hematidrosis, fear and anxiety seem to be the most commonly reported. The body's natural fight-or-flight reflexes may lead to capillary rupture, causing droplets of blood to enter the nearby sweat glands and exiting the body through perspiration. Excessive physical exertion, psychogenic purpura, and vicarious menstruation are other potential causes of hematidrosis.

Extreme fear and anxiety may cause hematidrosis.
Extreme fear and anxiety may cause hematidrosis.

Psychogenic purpura is a possible contributing factor to the development of hematidrosis. This is a rare condition in which painful lesions appear on the face and extremities. Psychogenic purpura is poorly understood and is thought to be related to mental illness, sometimes resulting in what has often been termed hysterical bleeding. Blood tests and other types of diagnostic testing do not lead to any abnormal results, contributing to the difficulty in scientifically understanding this phenomenon.

Vicarious menstruation may cause hematidrosis.
Vicarious menstruation may cause hematidrosis.

Vicarious menstruation has been listed as yet another possible cause for hematidrosis in some women. This condition is marked by bleeding from parts of the body other than the uterus at the normal time of menstruation. This is thought to occur due to the increased capillary permeability that naturally occurs during menstruation. The reasons for this occurring in some women but not in others is not clinically understood.

Hematidrosis is a rare condition that causes a person to appear to sweat blood.
Hematidrosis is a rare condition that causes a person to appear to sweat blood.

Despite this condition being extremely rare and having no scientific evidence to support the existence of hematidrosis, sweat mixed with blood has been reported for many centuries throughout the world. In almost all of the reported cases, the affected person has been facing bouts of extraordinary fear, often at anticipating death or other types of physical injury. The physical dehydration that occurs in moments of extreme stress, anxiety, and fear is thought to be a contributing factor in the development of this condition. Any instances of blood being present when perspiring should be reported to a doctor for further medical evaluation.

Discussion Comments


@ceilingcat - I'm glad panic attacks don't usually lead to hematidrosis. I get panic attacks, and the last thing I need during a panic attack is to be sweating blood!

Which brings me to another point. It would be horrible to experience hematidrosis because of psychogenic purpura (which sounds pretty awful one its own.) Usually most mental conditions manifest in non-visible ways. You feel terrible, but you don't break out into lesions or sweat blood.

I can imagine something like this would distress someone who was already having difficulty even further.


@starrynight - Well, I've never heard of hematidrosis before this, so if I saw someone that was sweating blood, I don't think I would assume "hey, they're on their period." So any sufferer of vicarious menstruation is probably safe from period embarrassment (which I've never understood anyway, it's just a bodily function.)

I find it very interesting that hematidrosis doesn't happen very often. If it's possible caused by severe stress and anxiety, why don't people with panic attacks suffer from hematidrosis? Or people who are under extreme pressure at their jobs?


I am horrified by the idea of hematidrosis being caused by vicarious menstruation. Most women go through great lengths to hide the fact that they're on their periods. We carry our purses to the bathroom while we're at the office instead of just carrying a pad of a tampon. I know a lot of women who are embarrassed even buying these products, and talk about "that time of the month" in hushed tones.

Imagine if your period caused you to sweat blood! I guess not everyone is aware that hematidrosis can be caused by vicarious menstruation, but maybe for some it would be obvious. Either way, it would be extremely embarrassing.


@everetra - I once read a medical diagnosis of what happened to Jesus from Gethsemane to the cross. It’s quite possible that your analysis is correct.

It’s illuminating that such a thing rarely occurs, which does give a clear insight into the magnitude of the duress during that time. However let’s not forget that there are other reasons that people could bleed spontaneously.

I have sometimes gotten up in the morning with some slight bleeding in my nose, because of improper humidity during the night. So that could be a factor too in my opinion.

I think that the reason scientists don’t really understand the condition is that it rarely happens – so they have few opportunities to study it. The real cause is anyone’s guess at this point I suppose.


The Bible says the Jesus sweat blood, literally, during His time in Gethsemane. Is it possible that this was the condition described here?

It could have been hematidrosis, in my opinion, or it could have been sweat mingled with blood – who knows. It’s clear that Gethsemane was a moment of extreme anxiety just prior to the cross.

I honestly can’t think of many contemporary examples where something like that could happen. I suppose being a POW in war time could be such a situation, or any other situation where you know that you are headed for death. I can’t imagine myself not sweating, blood or regular sweat, in such a situation.

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    • Extreme fear and anxiety may cause hematidrosis.
      By: vladimirfloyd
      Extreme fear and anxiety may cause hematidrosis.
    • Vicarious menstruation may cause hematidrosis.
      By: romikmk
      Vicarious menstruation may cause hematidrosis.
    • Hematidrosis is a rare condition that causes a person to appear to sweat blood.
      By: mizina
      Hematidrosis is a rare condition that causes a person to appear to sweat blood.