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Eosinophilia is characterized by an increase in eosinophils (type of WBCs) in the blood. It is caused by a variety of factors. WBCs play a critical role in the defense system as it has an anti-infection response that assists in the body’s protection. Eosinophils are a kind of white blood cell. They participate in both the body’s normal physiological functions and the host’s defense. Additionally, they participate in the control of allergic responses and parasite resistance.When the body is sick, eosinophils help the body fight the disease. The most common causes of peripheral eosinophilia include parasite infection, an allergic reaction, or malignant development.

Eosinophilia is defined as the presence of more than 500 eosinophils per microliter of blood; however, the precise threshold varies by laboratory. Eosinophilia is classified into three severity levels: mild, moderate, and severe.Eosinophilia symptoms include itching, rash, asthma, diarrhea, and runny nose.

The quantity of WBCs/eosinophils in the body is determined by an absolute eosinophil count. EOS absolute is a kind of blood test. Your eosinophils become more active when you have certain allergies, diseases, infections, or other medical issues. On the other hand, low eosinophils may indicate a bone marrow problem.


Eosinophils have a dual function in the immune system. Elimination of undesirable pathogens and inflammation. They combat chemicals associated with a parasite infection that your immune system has identified as requiring elimination. Eosinophils have a role in the formation of inflammation. Inflammation may sometimes become more severe than necessary, resulting in unpleasant symptoms or even tissue damage. Eosinophils in this case leads to the development of asthma and allergies such as hay fever. Chronic inflammation may be caused by a variety of immune system problems, including autoimmune diseases.

Eosinophilia causes include:

  •         Allergic reactions
  •         Skin infections
  •         Toxins accumulation
  •         Endocrine disorders
  •         Fungal or parasitic infections
  •         Tumors

A disease that causes abnormally high eosinophil count include:

  •         Acute myelogenous leukemia
  •         Asthma
  •         Cancer
  •         Crohn’s disease (an inflammatory condition)
  •         Hodgkin’s lymphoma
  •         Immunodeficiency
  •         Colitis

These diseases are able to cause blood and tissue eosinophilia.

Eosinophilia myalgia syndrome is an inflammatory disorder that affects the muscles, skin, and lungs. This syndrome is also responsible for causing abnormally high numbers of eosinophils in the blood as it is accompanied by inflammation. Severe muscle pain, muscle spasm, fatigue, joint pain, swelling and itching are the symptoms accompanied by eosinophilia.

Drug reactions also cause eosinophilia. Certain medicines may induce eosinophilia, which may present itself without obvious signs or symptoms. Antibiotics and anti-inflammatory medicines are the most often given medications that cause eosinophilia. Eosinophilia and systemic symptoms are two indications of a severe drug reaction.

Another cause of eosinophilia is atopy. Atopy is a kind of allergic reaction. Acne, asthma, and seasonal allergies are all types of atopy. It is the cause of mild to moderate eosinophilia, which is more common in children and adolescents. Food allergies, on the other hand, may also result in an increase in the number of eosinophils in the blood.

Cancer is also linked with eosinophilia. There has been an increase in eosinophil count, a sign of inflammation, in a variety of malignancies, most notably blood cancers.


Various conditions, including infections, allergies, and pharmaceutical reactions, can cause eosinophilia. To help rule out these other causes, your doctor will likely inquire about your travel history and any drugs you’re taking while determining whether you have hypereosinophilic syndrome (HES).

Your doctor may also require results from the following lab tests for eosinophilia diagnosis:

  • Blood tests to diagnose autoimmune diseases, parasite infections, or liver or kidney disorders
  • Environmental or food allergies can be detected with allergy testing.
  • Stool tests for parasitic diseases like hookworm
  • A genetic test is performed for a gene mutation that can lead to HES


Eosinophilic treatment aims to lower your eosinophil level in order to prevent tissue damage, particularly to your heart. The type of treatment you receive is determined on your symptoms, the severity of your condition, and the cause of your eosinophilia.

If you have no symptoms and your eosinophil level is low enough, you may not need therapy other than close monitoring for eosinophilia-related changes.

When To See A Doctor

Eosinophilia is often discovered because of blood tests performed by a doctor in order to aid in the diagnosis of a disease from which you are already experiencing symptoms. Consult with your doctor to determine the significance of these findings. Eosinophilia in the blood or tissues, in conjunction with the findings of other tests, may assist in identifying the cause of your disease. Getting an appropriate diagnosis and being able to get treatment for any relevant diseases or disorders will almost certainly result in a reduction in eosinophilia. Eosinophilia is a serious condition that necessitates immediate medical attention, if not treated promptly then it may lead to fatal consequences.


This information is intended for educational purposes only and should not be considered a substitute for professional medical advice. If you have concerns about eosinophilia or any other medical condition, please see a doctor for an accurate diagnosis and personalized treatment suggestions.