What is hematidrosis?

Hematidrosis is an extremely rare condition in which you sweat blood. It’s also known as hematohidrosis and hemidrosis. It’s so rare that many people don’t know it exists or if it’s real. But sweating blood has been seen throughout history. The Bible mentions Jesus sweating blood while praying before the crucifixion. Leonardo Da Vinci wrote about soldiers sweating blood before battle.

While these may or may not have been real depictions, hematidrosis is a real condition. Blood sweat can occur on any surface of the body. The face and forehead are common locations.

Learn more about why sweating blood happens and how doctors treat it.

There isn’t much information available on hematidrosis. Because it’s so rare, it isn’t clearly understood. However, hematidrosis generally happens when a person feels intense fear or stress. Someone facing death may have this kind of fear or stress, for example. When you are under stress, your body goes into flight-or-fight mode.

This is a natural reaction to a perceived threat. It helps us survive potentially dangerous situations. The body releases chemicals, like adrenaline and cortisol, that prepare us either to fight or to flee danger. We become more alert and our energy increases. This bodily response is usually temporary and doesn’t cause long-term health damage.

But in rare instances, the flight-or-fight response can trigger the rupture of capillaries in the body. Capillaries are tiny blood vessels located throughout tissue. They carry essential nutrients to different parts of the body. Capillaries are also located around the sweat glands. In cases of severe fear or stress, these tiny blood vessels can burst and cause blood to exit the body through the sweat glands.

Other possible causes

A ruptured capillary is the recognized cause of hematidrosis, but there have been other possible theories for bleeding through the skin. These include vicarious menstruation, which is when blood exits the body from a site other than the uterus during menstruation.

Another theory is psychogenic purpura. Psychogenic purpura is spontaneous bleeding and bruising without injury or other known cause.

Hematidrosis doesn’t appear to be life-threatening. Because so little is known about hematidrosis, there aren’t clear guidelines for how to address it. To stop bleeding from the skin’s surface, treatment will usually address the underlying stressor that’s triggering the disorder.

Your doctor may do a variety of diagnostic tests. These can help them to:

  • check blood count
  • check platelet count
  • rule out possible bleeding disorders

Some doctors also order laboratory tests to check kidney and liver function. They may order a urine and stool sample to check for abnormalities. An ultrasound of your abdomen or endoscopy of your gastrointestinal tract can also help rule out other conditions.

If lab tests don’t find any abnormalities, and if you’ve also been under extreme stress, your doctor may suggest treatment to help you cope with fear, stress, and other emotions. This can include taking a prescription antidepressant or anti-anxiety medication. Your doctor may also recommend psychotherapy.