What Is Eosinophilia?
Eosinophilia is the presence of a high number of eosinophils (a type of white blood cell) in the blood. According to scientific sources, it is a common fact in clinical practice and it is not a pathology in itself, rather it is an immune response.
The importance of this event lies on two fronts: diagnostic and pathogenic. On the one hand, eosinophilia suggests the presence of an infection in the patient, but on the other, the release of products from these white blood cells can be associated with tissue damage.
Thus, we are facing a normal response by the immune system that can get out of control and cause damage. Here we tell you everything you need to know about it.
What is eosinophilia?
According to the medical literature, eosinophilia is considered to exist when the total number of circulating blood eosinophils is significantly higher than the values presented in the normal population. According to different authors, there are different limits to suggest this picture. Some of them are the following:
- Bridgen defines eosinophilia as values greater than 700 eosinophils per cubic millimeter of blood.
- Other researchers place this value between 350 and 600.
- In general, it can be concluded that more than 500 eosinophils per cubic millimeter of blood give rise to eosinophilia.
In turn, this abnormal presence of white blood cells can be divided into groups based on leukocyte abundance. Pediatric presentations include these categories:
- Mild: less than 1500 total eosinophils per cubic millimeter. Without other alterations, it is usually a benign process, so it does not require further studies.
- Moderate: a count of 1,500 to 5,000 eosinophils. If it occurs on at least two separate occasions or for more than a month, it requires study.
- Severe: more than 5000 eosinophils per cubic millimeter of blood. It should be noted that an eosinophilia of more than 20,000 requires hospitalization and, in cases of more than 100,000, immediate admission of the patient and treatment with corticosteroids is essential.
Finally and to end this whole conglomerate of classification, according to its causative agent, eosinophilia is divided in two. It can be primary (by bone marrow mutation) or reactive (by external agents).
Causes of eosinophilia
Eosinophils are components of the immune system that fight external infections, either by destroying foreign bodies or regulating inflammatory processes. They allow to control and isolate the foci of disease.
Thus, it is not surprising to learn that eosinophilia is widely associated with allergies, neoplasms, or the presence of parasites in the host. In industrialized countries, the most common cause of eosinophilia is allergic processes, while in other places it is infections by parasites.
Based on the Mayo Clinic and other sources already cited, we show you the most common causes.
1. Allergic diseases or with atopy substrate
Atopic disease (allergy) is the most common cause of eosinophilia in Western countries. It appears in cases of dermatitis, asthma and rhinitis, but they are always low blood cell counts.
This increase in leukocytes can also be associated with hypersensitivity to certain drugs, such as antidepressants, anti-inflammatories or antibiotics. Food is another not uncommon origin.
2. Neoplasms
Neoplasms, that is, the growth of abnormal masses, both cancerous and non-cancerous, are associated with eosinophilia. The most common diseases are Hodgkin’s lymphoma (up to 15% of those affected have it), other non-Hodgkin’s lymphomas, and various types of leukemia.
3. Infections
According to medical sources, helminth parasite infections are the most widespread cause of eosinophilia worldwide. This is because helminthiases are very common in tropical countries, where food conditions and sanitary structures are poor.
It should be noted that, in general, viral and bacterial infections cause eosinopenia (eosinophil deficiency), so this condition is reserved for infections by parasites such as Anisakis , E. granulosus, Fasciola hepatica, Tapeworms, Trichinella and many other parasitic pathogens.
Can eosinophilia be prevented?
This question will have a different answer depending on the concept of prevention. Can asthma be prevented? Can lymphomas be prevented? Are there ways to reduce parasitosis in tropical countries?
The answer, in principle, is no. A mild eosinophilia is a common immune response of the body when it is fighting certain pathogens and is not bad in itself, so it cannot and should not be prevented. Only in severe cases must measures be taken and these can be carried out by medical professionals in a hospital setting.
Eosinophilia: what to remember?
As we have seen, a moderately high blood eosinophil count is normal and does not require any treatment. It is a natural immune response to allergic processes and parasitic infections.
Still, if the numbers skyrocket or if the elevated number of eosinophils persists over time, it may be time to suspect a serious underlying condition. In any case, the diagnostic process must be guided by a health professional who establishes the steps to follow.
