Eosinophilia is a condition that is characterized by abnormal levels of eosinophils, which are one of the five main types of infection-fighting white blood cells.
When the level of eosinophils in the blood is high, then it is known as blood eosinophilia. High level concentration of eosinophils at various sites such as inflamed areas or infected regions, results in the development of tissue eosinophilia.
Diagnosis of Eosinophilia
One can diagnose the presence of blood eosinophilia, when an individual undergoes a blood test, and the diagnosis is generally inferred from a complete blood count test. Adults with an eosinophils count of above 500 eosinophils per micro-liter of blood are usually diagnosed as having eosinophilia. Hypereosinophilic syndrome is a condition wherein, the eosinophils count is above 1,500 eosinophils per micro-liter of blood for a period of many months.
One can detect the presence of tissue eosinophilia during examination of tissue samples taken as a routine or exploratory test, or in sample of some fluids like mucus that is secreted from the tissues in the nose. The levels of eosinophils in the blood stream are most likely to be normal, when an individual is affected by tissue eosinophilia.
Two essential roles are played by eosinophils in the immune system, as discussed below:
- Eosinophils are responsible for regulation of inflammation. They aid the promotion of inflammation, thereby facilitating the control and isolation of a disease site. But it should also be remembered that tissue damage can also occur due to inflammation. Eosinophils are essential in regulating inflammation associated with asthma and allergies.
- Eosinophils are responsible for the destruction of foreign particles that have considered as harmful by the immune system of the body. It is more so in the case of particles that are associated with parasitic or other infections.
- Eosinophilia signs and symptoms are similar to those elicited by the pre-existing condition. For example, eosinophilia that results from asthma can lead to the development of symptoms such as shortness of breath, wheezing, etc., while infections by parasites can cause diarrhea, rashes, pain in the abdomen, cough or fever.
- Night sweats, enlargement of the lymph node, loss of weight and tingling and numbness as a result of nerve damage are some of the rare symptoms of eosinophilia
- Eosinophilia symptoms, such as skin rashes, can occur as part of reactions to certain medications, especially when the medicine that is consumed is a new drug.
- Hypereosinophilic syndrome can damage the heart leading to cardiac failure and associated symptoms such as shortness of breath and swollen ankles; can cause development of rashes on the skin, and also result in enlargement of the spleen and liver leading of symptomatic abdominal swelling.
Causes of Eosinophilia
Eosinophilia is caused due to increased concentration of eosinophils at a particular site in the body, or when there is excessive production of eosinophils by the bone marrow. This can be the result of a number of factors, diseases and disorders such as:
- Fungal and parasitic infections
- Adrenal disorders
- Allergies that may include allergic reaction to food as well as drugs
- Skin diseases
- Autoimmune conditions
- Disorders of the endocrine system
Some of the disorders, diseases and factors that can cause tissue or blood eosinophilia include the following:
- Eczema or atopic dermatitis
- Chronic myelogenous leukemia
- Crohn’s disease
- Churg-Strauss syndrome
- Allergies to certain medications
- Hay fever
- Eosinophilic leukemia
- Hodgkin’s disease or Hodgkin’s lymphoma
- Lupus disease
- HES or idiopathic hypereosinophilic syndrome, whose origins are unknown and which causes very high levels of eosinophil count
- Lymphatic filariasis which is a type of parasitic infection)
- Various other cancers
- Non-Hodgkin’s lymphoma
- Infections by various other parasites
- Primary immunodeficiency
- Ovarian cancer
- Scarlet fever
- Ulcerative colitis
- Trichinosis, which is a type of roundworm infection
Allergic reactions to drugs and parasitic infections are considered as the most likely causes of eosinophilia. The cause of hypereosinophilic syndrome may result from some forms of cancers, like lymph node or bone marrow cancer, or may have unknown causes.
Treatment of eosinophilia involves diagnosis of the underlying condition that has resulted in eosinophilia.
- The doctor may conduct blood and skin tests to detect the presence of certain allergies, like allergy to dust mite or pollen, etc. The stool and blood samples may be examined for confirmation of parasitic infections. If a particular medication is causing eosinophilia then the intake of that drug should be immediately stopped and alternative medications will be suggested by the doctor. In case, the regular health care provider is unable to diagnose the cause of eosinophilia, then the patients have to contact a specialist for effective diagnosis.
- The various causes such as allergic reactions, parasitic infections, etc. are then treated with various medications which are non-toxic and effective.
- Corticosteroids are usually used to treat hypereosinophilic syndrome. In case this therapy does not yield any results then chemotherapeutic agent is generally prescribed.