Hyperemia describes an excess of blood in the blood vessels in a specific part of the body.

It comes from the Greek words hupér, meaning over, and haîma, meaning blood.

In this article, we examine what hyperemia is, along with its causes and symptoms. We also take a look at the difference between active and passive hyperemia.

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Hyperemia is an excess of blood in blood vessels and may look red and warm, such as when a person blushes.

Hyperemia occurs when excess blood builds up inside the vascular system, which is the system of blood vessels in the body.

When excess blood occurs outside the vascular system, due to a broken blood vessel or injury, this is known as hemorrhage.

The buildup of blood may present as a red, warm, painful, swollen area. These signs, along with loss of function, are considered the original five signs of inflammation defined by the Greek philosopher Celsus.

Hyperemia can be broken down into two types: active and passive.

These types can then be further divided into local hyperemia (meaning in a specific area) or general hyperemia (affecting a whole system in the body).

Hyperemia can be acute or chronic, meaning it can happen quickly and for a short time or may persist over a longer term.

Active hyperemia

Active hyperemia is a physiological response to something happening in the body. It is an acute form of hyperemia.

For example, there is more blood in the digestive system after a meal, more blood in the muscles after exercise, and more blood in the face when a person blushes.

Increased blood flow and redness occur when there is a demand for oxygen and nutrients in a particular area.

The two different types of active hyperemia are:

  • Acute general active hyperemia: When there is increased blood flow throughout the body.
  • Acute local active hyperemia: When there is an increased amount of blood in a local area such as the leg, stomach, or lung. This is the most common form of hyperemia.

Passive hyperemia

Also known as congestion, passive hyperemia can be either acute or chronic.

Chronic passive hyperemia usually occurs in the organ systems of the lung, liver, and lower extremities.

It may be localized to one area. However, if the blood flow in the heart is being impeded, then it will affect the whole system.

This occurs when there is a decreased outflow out of the blood vessels.

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Inflammation and exercise may be causes of active hyperemia.

The causes of hyperemia vary depending on whether it is active or passive.

Causes of active hyperemia include:

  • exercise
  • inflammation
  • menopausal flush
  • diseases that make the heart beat rapidly
  • renal diseases that cause fluid retention

Causes of passive hyperemia include:

Another cause of passive hyperemia is the inability of the heart to pump blood efficiently, causing a buildup of too much blood in areas leading to the heart.

In right-sided heart failure, the blood backs up into the liver. In left-sided heart failure, the blood backs up into the lungs.

Right-sided heart failure

If the problem is on the right side of the heart, it can cause congestion in the liver, spleen, kidney, or leg.

This can lead to what is known as “nutmeg liver” due to the mottled pattern that appears on the liver. The liver will also be enlarged, red or reddish-blue in appearance, and surrounded by brownish-yellow fatty liver cells.

Over time, this can cause cirrhosis, which is scarring caused by long-term liver damage and can ultimately lead to liver failure and death.

Left-sided heart failure

The lungs are more likely to be affected if there is a problem with the left side of the heart. The lungs will appear dark red and there may be excess fluid in the lungs.

Heart failure in one side can eventually lead to failure in the opposite side as well.

Hyperemia can change the tissue in the affected area. People with active hyperemia may notice one or more of the following symptoms:

  • bright red in color
  • warmer than usual to touch
  • swelling
  • easily felt pulse

Passive hyperemia affects the tissue differently and has the following symptoms:

  • dark blue or red tinge
  • swollen
  • cooler than usual to touch
  • in chronic cases, brown in color

Effects and complications

The type of hyperemia a person has will determine what kind of complications may occur.

For example, acute local active hyperemia may be a sign of inflammation. Acute local passive hyperemia could be due to intestinal or uterus torsion.

Chronic local passive hyperemia could indicate that tumors or abscesses are developing in the body.

Passive hyperemia, or congestion, is linked to heart problems and will affect different organs in the body depending on which part of the heart is affected.

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Passive hypereemia is associated with heart failure, so eating a heart-healthy diet is recommended.

The treatment of hyperemia will focus on the cause.

Active hyperemia does not typically need to be treated, as it is a physiological response to activities such as physical exercise and will improve on its own.

Passive hyperemia, however, is caused by other conditions that will need to be treated.

Medication for hyperemia causes may include:

Active hyperemia is a beneficial response to help the body obtain oxygen and nutrients.

Passive hyperemia is closely associated with heart failure. There are several lifestyle changes people can make to avoid this:

  • eating a heart-healthy diet
  • exercising regularly
  • losing weight if overweight