Eosinophils: what it means when they are high or low

Eosinophils are a type of blood defense cell that originates from the differentiation of a cell produced in the bone marrow, the myeloblast, and aims to defend the organism against the invasion of foreign microorganisms, being very important for the action of the immune system.

These defense cells are present in the blood in high concentrations mainly during allergic reactions or in case of parasitic, bacterial and fungal infections. Eosinophils are usually in lower concentrations in the blood than other defense cells in the body, such as lymphocytes, monocytes or neutrophils, which also act on the immune system.

Reference values

The amount of eosinophils in the blood is assessed on the leukogram, which is a part of the blood count in which the body's white cells are assessed. The normal values of eosinophil in the blood are:

Absolute value: 40 to 500 cells / µL of blood - is the total count of eosinophils in the blood; Relative value: 1 to 5% - is the percentage of eosinophils in relation to the other cells of the white blood cell.

The values may change slightly according to the laboratory in which the exam was performed and, therefore, the reference value must also be checked in the exam itself.

What can be altered Eosinophils

When the test value is outside the normal range, it is considered that the person may have increased or decreased eosinophils, each change having different causes.

1. Tall eosinophils

When the eosinophil count in the blood is greater than the normal reference value, eosinophilia is characterized. The main causes of eosinophilia are:

Allergy, such as asthma, hives, allergic rhinitis, dermatitis, eczema; Worm parasites, such as ascariasis, toxocariasis, hookworm, oxyuriasis, schistosomiasis, among others; Infections, such as typhoid fever, tuberculosis, aspergillosis, coccidioidomycosis, some viruses; allergy to the use of medicines, such as ASA, antibiotics, antihypertensives or tryptophan, for example; Inflammatory skin diseases, such as bullous pemphigus, dermatitis; Other inflammatory diseases, such as inflammatory bowel disease, hematological diseases, cancer or genetic diseases that cause hereditary eosinophilia, for example.

In some rare cases, it is still possible not to discover the cause of the increase in eosinophils, a situation called idiopathic eosinophilia. There is also a situation called hypereosinophilia, which is when the eosinophil count is very high and exceeds 10, 000 cells / µL, being more common in autoimmune and genetic diseases, such as hypereosinophilic syndrome.

How to know if I have eosinophils above normal

A person who has high eosinophils does not always show symptoms, but they can arise from the very disease that caused eosinophilia, such as shortness of breath in cases of asthma, sneezing and nose congestion in case of allergic rhinitis or abdominal pain in cases of infections parasitic, for example.

As for people who have hereditary hypereosinophilia, it is possible that excess eosinophils cause symptoms such as pain in the belly, itchy skin, fever, body pain, abdominal cramps, diarrhea and nausea.

Eosinophil in blood sample

2. Low eosinophils

The low eosinophil count, called eosinopenia, happens when eosinophils are below 40 cells / µL, and can reach 0 cells / µL.

Eosinopenia can happen in the case of acute bacterial infections, such as pneumonia or meningitis, for example, since they are serious bacterial infections that usually increase other types of defense cells, such as neutrophils, which can decrease the absolute or relative count of eosinophils. The reduction in eosinophils may also be the result of decreased immunity due to illness or use of drugs that alter the function of the immune system, such as corticosteroids.

In addition, it is possible to have low eosinophils without changes being found. This situation can also arise in pregnancy, when there is a physiological reduction in the count of eosinophils.

Other rare causes of eosinopenia include autoimmune diseases, bone marrow diseases, cancer or HTLV, for example.