What Is Hyperemia?

Medically Reviewed by Carmelita Swiner, MD on July 07, 2023
Written by WebMD Editorial Contributors
3 min read

Hyperemia is when your blood adjusts to support different tissues throughout your body. It can be caused by a variety of conditions. There are two types of hyperemia: active and passive. Active hyperemia is quite common and not a medical concern. Passive hyperemia is usually caused by disease and is more serious.

There are two types of hyperemia: active hyperemia and passive hyperemia. People usually experience active hyperemia as a healthy physical response. But passive hyperemia is often a response to disease or distress. ‌

Active Hyperemia is blood moving towards an organ. Causes include:

  • Exercise. When you exercise and physically exert yourself, your cardiovascular system, heart, respiratory muscles, and active skeletal muscles all have to work harder. This means your body needs more blood and oxygen, which causes hyperemia.
  • Digestion. After you eat and start digesting, your body sends more blood to the stomach and intestines to fully break down your food. 
  • Fever. These are when your internal body temperature rises past the normal rate, usually past 100 degrees. Fevers can cause hyperemia due to the body’s attempt to release some of that internal heat to the skin. 
  • Hormonal irregularities. There are specific hormonal conditions, like perimenopause, that cause hot flashes throughout the body. These hot flashes can cause hyperemia as the blood rushes to the skin. 
  • Blushing. This is when your face goes red because you feel embarrassed, guilty, or ashamed. Blushing happens through the complex and sensitive neurological blood system in your face. The redness is due to hyperemia. 
  • Injury and infection. During an injury, your body uses blood to help stop bleeding and also guard against infection. The blood also carries immune cells, which help your body to repair itself. 
  • Blockage. Long periods of inactivity or bed rest can cause blocked arteries or veins. The blockage is caused by the way you position your body. When certain parts of your body are blocked, other parts of your body can experience hyperemia or a buildup of blood. Moving your body can cure this. 

Passive Hyperemia is when parts of the body are clogged, or the blood is clotted and can't flow. These conditions happen within your blood and organs, and may include:

  • Heart failure. The heat’s job is to pump blood through the body. One part of the heart takes in blood, and the other part sends it out to the rest of the body. Heart failure is when the heart is clogged and can't complete this process. Heart failure is extremely dangerous and can immediately affect the liver, kidneys, spleen, and lungs.
  • Clotting. Also known as thrombosis, this is when a blood clot happens in a passageway for blood. Clots block the blood from flowing throughout the body and cause build-ups in certain areas.

Thrombosis can be caused by: 

  • Broken bones
  • Medications
  • Injury
  • Obesity 
  • ‌Immobility
  • ‌Pregnancy
  • ‌Central catheter
  • ‌Clotting disorders 
  • ‌Smoking 
  • ‌Diabetes
  • ‌High blood pressure
  • ‌High cholesterol
  • ‌Surgery

Active hyperemia is usually uneventful and harmless. You might notice redness and warmth on your skin. It can look different depending on the cause and type of hyperemia you have. 

If you or your doctor suspect you have passive hyperemia, you will likely get tested. Some of the symptoms of passive hyperemia are:

  • Trouble breathing
  • Pain in the chest
  • Coughing
  • Wheezing
  • Swelling in the limbs
  • Nausea
  • Pain
  • Itchiness

It would be unusual to get tested and diagnosed with active hyperemia. Active hyperemia has clear symptoms and isn't usually a cause for concern. But passive hyperemia has severe medical implications. If your doctor thinks you may have passive hyperemia, they will give you the following tests:

Active hyperemia is a healthy response to your body’s natural functions. While you may need to treat the underlying conditions that can cause hyperemia (injury, fever, inflammation), it's not usually anything to worry about. 

The treatments for passive hyperemia are more extensive and may involve significant lifestyle changes. These can include:

  • Diet changes 
  • Increasing exercise 
  • Weight loss
  • Stopping smoking‌

Medical treatments can include: