Eosinophil levels can help provide some information about a person’s overall health. Low numbers may indicate excessive stress, alcohol misuse, or the presence of an underlying condition.

Eosinophils are a type of white blood cell found throughout the body. They play a role in the immune system by helping to fight bacterial and viral infections and can also play a role in the inflammatory response to an allergen.

A doctor can check eosinophil levels using a complete blood count (CBC) or WBC count.

An eosinophil count refers to the number of eosinophils in the body. Most adults have an upper limit of roughly 500 eosinophil cells per microliter (μL) of blood.

Higher counts can indicate the presence of an infection or other issues. When a test reveals a person has a higher eosinophil count than expected, they likely have a condition known as eosinophilia.

Lower numbers may indicate potential health problems. When a person’s eosinophil levels are low, they might be at an increased risk of certain health conditions, such as heart failure.

Eosinopenia describes when a person has a lower number of eosinophils than expected. A health expert may use this term when a person has less than 100 cells per μL of blood.

Most adults have relatively low blood eosinophil levels. However, since some underlying conditions can suppress eosinophils and other WBCs, a doctor may want to check for lower than usual eosinophil levels to help identify conditions and confirm a diagnosis.

This article details possible symptoms, complications, causes, diagnosis, and treatment options related to low eosinophil levels.

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A person with low eosinophil levels is not likely to experience any symptoms. Their levels are generally low, with most adults having less than 500 cells per μL of blood.

However, a person may notice symptoms associated with an underlying condition affecting their counts. For example, a person with Cushing’s syndrome may experience weight gain in their face, midsection, or back of their neck, general fatigue, or easy bruising, among other symptoms.

Lower numbers of eosinophil levels could be potentially fatal. According to a 2016 study, lower levels of eosinophil and other WBCs increase the short-term risk of heart failure and coronary-related death.

Low eosinophil levels have several potential causes, including:

  • Acute infections: When an infection affects an area of the body, it can send signals to attract eosinophils to the tissue. This can cause a drop in blood count levels. Bacterial infections, such as sepsis, can often lead to drops in eosinophil levels.
  • Certain medications use: Some medications suppress the immune system, which can lead to lower levels of eosinophils. For example, glucocorticoids are anti-inflammatory medications used to treat different lung conditions. Their usage can lead to suppressed eosinophil levels.
  • Cushing’s syndrome: This is a hormonal condition that occurs when a person’s cortisol levels are too high. It may occur due to cortisol medication usage or certain underlying health conditions. Cortisol helps suppress the immune system and can lead to decreased eosinophil levels in the blood.
  • Alcohol misuse: Alcohol misuse may impact the levels of eosinophils, and other WBCs, causing them to drop. This can reduce the body’s immune system response to infections and other disease states.

A healthcare professional can check eosinophil levels during a routine complete blood count or WBC blood draw. Eosinophil levels are generally low, with most adults having less than 500 cells per μL of blood. When a person’s numbers are unusually low, the doctor may also check other WBC levels. Overall low levels may indicate a potential underlying issue.

A doctor may suspect eosinopenia if a person:

  • takes cortisol steroids
  • use medications such as glucocorticoids
  • previous diagnosis of Cushing’s syndrome
  • show signs or symptoms of an infection

Low eosinophil levels may not need treatment. If a doctor suspects a medication is causing the problem, they may recommend changing medications.

A doctor will likely recommend treatment if eosinopenia is due to an underlying condition. For example, sepsis is a serious condition and a leading cause of death worldwide, with a mortality rate greater than 40%.

To treat sepsis, a doctor may suggest steroids to help control inflammation. Other treatments may include antibiotics and blood pressure medications.

Eosinophils are a type of white blood cell that can help fight off bacterial and viral infections. As eosinophil levels are naturally low in adults, a doctor may not take steps to treat them unless they suspect an underlying cause or a person also presents with low levels of other white blood cells.

Possible causes of eosinopenia may include sepsis, Cushing’s syndrome, and the use of certain medications. If a doctor suspects one of these issues, they may take steps to manage the person’s underlying cause and eosinophil levels in general.