Eosinophilia (e-o-sin-o-FIL-e-uh) is a higher than normal level of eosinophils. Eosinophils are a type of disease-fighting white blood cell.
You can have high levels of eosinophils in your blood (blood eosinophilia). High levels of eosinophils may also occur in your body's tissues at the site of an infection or inflammation (tissue eosinophilia).
Tissue eosinophilia may be found in samples taken during an exploratory procedure or in samples of certain fluids, such as mucus released from nasal tissues. If you have tissue eosinophilia, the level of eosinophils in your bloodstream is likely normal.
Blood eosinophilia may be detected with a blood test, usually as part of a complete blood count. A count of more than 500 eosinophils per microliter of blood is generally considered eosinophilia in adults. A count of more than 1,500 eosinophils per microliter of blood that lasts for several months is called hypereosinophilic syndrome.
Eosinophilia occurs when either a large number of eosinophils are recruited to a specific site in your body or bone marrow produces too many eosinophils. This can be caused by a variety of conditions, diseases and factors, including:
- Parasitic and fungal diseases
- Allergies, including to medications or food
- Adrenal conditions
- Skin disorders
- Autoimmune diseases
- Endocrine disorders
Specific diseases and conditions that can result in blood or tissue eosinophilia include:
- Ascariasis (a roundworm infection)
- Atopic dermatitis (eczema)
- Chronic myelogenous leukemia
- Churg-Strauss syndrome
- Crohn's disease
- Drug allergy
- Eosinophilic leukemia
- Hay fever
- Hodgkin's lymphoma (Hodgkin's disease)
- Idiopathic hypereosinophilic syndrome (HES), an extremely high eosinophil count of unknown origin
- Lymphatic filariasis (a parasitic infection)
- Other cancers
- Other parasitic infections
- Ovarian cancer
- Primary immunodeficiency
- Trichinosis (a roundworm infection)
- Ulcerative colitis
Parasitic diseases and allergic reactions to medication are among the more common causes of eosinophilia. Hypereosinophilic syndrome tends to have an unknown cause or results from certain types of cancer, such as bone marrow or lymph node cancer.
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.