What are eosinophils and what is their role in the body?

Eosinophils are a type of white blood cell and are an essential part of the human immune system. These cells play a significant role in defending the body against infections, particularly those caused by parasites and fungi. Eosinophils are also involved in allergic and inflammatory responses. Under normal conditions, eosinophils are not present in large numbers in the blood, but the body may produce more of them in response to certain conditions.

The role of eosinophils in the immune response

Eosinophils serve as an important line of defense against various pathogens. When the body faces a parasitic or fungal infection, eosinophils migrate to the site of the infection to assist in eliminating it. They also contribute to regulating other immune responses and release chemicals that help destroy invading cells or modulate inflammation. [3]

Eosinophils and allergic disorders

In addition to their role in fighting infection, eosinophils are closely linked to allergic disorders. In cases of allergy, eosinophils can accumulate in tissues and organs, leading to inflammation and damage. For example, in conditions such as allergic asthma or eosinophilic esophagitis, eosinophils migrate to these organs and cause characteristic symptoms of these conditions. [3]

When do eosinophil counts rise?

Eosinophil counts can rise in the blood or accumulate in tissues in response to several health conditions. Common causes of elevated eosinophils include: [3]

• Allergic disorders: Such as asthma, eczema, and allergic rhinitis.
• Parasitic and fungal infections: Where eosinophils play a key role in fighting these types of infections.
• Autoimmune diseases: Where the immune system mistakenly attacks the body's tissues.
• Certain types of cancer: Including bone marrow disorders.
• Certain drug reactions: Such as DRESS syndrome (Drug Rash with Eosinophilia and Systemic Symptoms), which is a severe allergic reaction to medication that can cause a skin rash, fever, and inflammation in various organs such as the liver, kidneys, and lungs. [1]

What does an elevated eosinophil count mean?

When eosinophil counts rise abnormally, whether in the blood or tissues, it is known as 'eosinophilia'. Eosinophils can move out of the bloodstream and accumulate in various organs and tissues, leading to inflammation and damage in those areas. This accumulation can affect multiple parts of the body, including the esophagus, heart, lungs, blood, and intestines. [3]

If tests show an increase in eosinophil counts, it may indicate an underlying medical condition that requires evaluation and treatment. Diagnosis may include procedures such as an upper gastrointestinal endoscopy (Arabic) if symptoms involve the digestive system, in order to take tissue samples for examination. [2] It is important to consult a physician to determine the underlying cause behind the elevated eosinophils and to develop an appropriate treatment plan, which often includes steroids to reduce inflammation.

Medical references

• Eosinophilic Disorders
• Drug rash with eosinophilia and systemic symptoms
• Upper GI Endoscopy