Eosinophils belong to the category of white blood cells. Their main function is working as the body’s natural defense against infections and diseases. Generally, eosinophil count is monitored by doctors to diagnose underlying health conditions. For example, eosinophil count may indicate the presence of allergies or if someone has an autoimmune disorder. Elevated eosinophils in a blood test indicate eosinophilia, a condition in which the body releases an excessively high number of eosinophils.

Here’s a look into some of the common causes and symptoms of eosinophilia and how it is diagnosed and treated.

What causes high eosinophils in blood test results?
A high eosinophil count might be observed in a blood test result for various reasons. Sometimes, the count reduces to normal levels without any treatment. In most cases, the causes are benign and do not require extensive medical intervention. Here are some of the common reasons why one may have eosinophilia.

• Parasite infections
  This type of infection is a common cause of eosinophilia. Some known parasitic infections that can cause a spike in eosinophils are trichinosis, schistosomiasis, ascariasis, and strongyloidiasis.
• Atopy
  This condition is a reaction that can occur in the body as a response to seasonal allergies, eczema, or asthma. Additionally, atopy can occur due to food allergies. A person may experience one or multiple reactions, resulting in elevated eosinophils in the blood.
• Eosinophilic esophagitis
  Also known as EoE, eosinophilic esophagitis is a health disorder that causes eosinophils to spread to the esophagus. Under normal circumstances, the esophagus does not have any eosinophils. EoE also causes the eosinophil count to spike in the bloodstream.
• Churg-Strauss syndrome
  Another common cause of eosinophilia is Churg-Stauss vasculitis. Also known as eosinophilic granulomatosis with polyangiitis, it causes lung problems such as asthma. In the advanced stages, the eosinophil levels are elevated, leading to inflammation of blood vessels or vasculitis.
• Cancer
  Elevated eosinophil count has been associated with several cancer types, specifically blood cancers. They include lymphoma, leukemia, colorectal cancer, lung cancer, myeloproliferative neoplasms, and cancer of the cervix.

Symptoms
Eosinophilia does not usually cause any symptoms. In most cases, an underlying condition or infection that is elevating the eosinophil levels causes certain symptoms to develop.

Generally, eosinophils work by releasing antibodies that eradicate infection-causing pathogens. In addition, the eosinophils send out alerts to other proteins and white blood cells at the site of the infection. A side effect of this internal process is an increase in inflammation. With eosinophilia causing an excess of eosinophils, the level of inflammation also increases. Additionally, in some medical conditions, the excess eosinophils tend to migrate and accumulate around several organs, such as the lungs, intestines, and skin. This leads to the development of several symptoms.

• Rashes
• Itching
• Swelling
• Lung congestion
• Diarrhea
• Cough
• Runny nose
• Wheezing
• Asthma

Diagnosis
Similar to other common types of blood disorders, eosinophilia is also diagnosed through a complete blood count (CBC). In the blood test, eosinophils can be identified under the white blood cell count marked as differential. The CBC differential indicates the count of different white blood types in the blood, such as neutrophil, monocyte, lymphocyte, basophil, and eosinophil.

The number of eosinophils will indicate whether a person has the condition or not. The normal count of eosinophils is less than 500 cells per microliter (cells/mcL). Here are the other ranges that indicate high eosinophils in blood tests.

• Mild: 500 – 1500 cells per microliter (mcL)
• Moderate: 1500 – 5000 cells/mcL
• Severe: more than 5000 cells/mcL

Once the results indicate high levels of eosinophilia, a healthcare provider will conduct diagnostic tests to identify the underlying cause. Generally, the cause is determined based on the symptoms presented. For instance, parasitic infections can cause diarrhea. Therefore, a doctor may order stool tests to get an accurate prognosis. Additionally, some additional tests may be recommended to determine the severity of the underlying condition. The tests may include:

• Liver function tests
• Urine tests
• Stool sample testing
• Additional blood tests
• Chest X-rays
• Tissue and bone marrow biopsies

Management options

Treating eosinophilia
The usual way to treat eosinophilia involves addressing the underlying health issue that is causing the elevated eosinophil counts. For example, if a person has EoE, a doctor will recommend certain prescriptions to manage the condition. And if the elevated eosinophil levels are due to an allergy or infection, a doctor may recommend allergy testing to identify which allergies or pathogens are causing the rise in eosinophil levels. Once the root cause is identified, a treatment plan will be developed to manage the allergy or infection, which will help reduce the eosinophil levels to normal range.

Management at home
In addition to doctor-recommended treatment plans, one can take certain measures to lower the number of eosinophils in the bloodstream. Here are a few tips that may help.

• Practice stress management techniques, as eosinophilia may occur due to conditions triggered by anxiety and stress. Minimize or avoid stressful triggers and learn to manage them with relaxation techniques such as yoga, massage therapy, or meditation.
• Try to avoid spaces that can trigger allergies and infections, especially during the seasons when allergies are quite common.
• Maintain basic cleanliness and hygiene at home to prevent dust mites, pollens, pet dander, and other allergy-causing substances from collecting on different surfaces.
• Eat foods with zero to minimal acidic content since heartburn and acid reflux have increased eosinophil counts. Instead, opt for lean meats, fresh veggies and fruits, and whole grains.