Eosinophilia -should i treat?

What is an eosinophil?

Eosinophils are differentiated white blood cells containing cytoplasmic granules that stain pink with eosin.

Differentiation and survival are promoted by cytokines, especially interleukin-5; therefore, an increase in eosinophils reflects inf lammation.

Eosinophil granules contain proteins that are cytotoxic to parasites and have a role in maintaining the body’sinflammatory response, but they can also cause organ damage when released in tissues

What is eosinophilia?


Eosinophils dwell primarily in tissues throughout the body and compose only a small percentage of peripheral blood leukocytes.

The absolute eosinophil count (AEC) is normally less than 450/mL(<0.45×109/L).

Eosinophilia is most often defined as an AEC greater than 500/mL(>0.5×109/L) and can be divided into 3 categories: mild (500–1,500/mL [0.5–1.5×109/L]), moderate (1,500–5,000/mL [1.5–5.0 ×109/L]), and severe (>5,000/mL[>5.0×109/L]).

What are the causes?

The differential diagnosis of eosinophilia is broad and includes benign conditions as well as disorders with potentially severe organ dysfunction and lifethreatening sequelae.

The degree of eosinophilia does not typically correlate with etiology or with severity of disease. Although classification schemas vary, most cases of eosinophilia during childhood are secondary to another disease state.


Allergic conditions, including asthma, allergic rhinitis, eczema, and urticaria, are the most common causes of mild to moderate eosinophilia for children

Although the eosinophil count is commonly suppressed in bacterial and viral infections, eosinophilia is typically present from the onset in parasitic infections. Tissue-invasive parasitessuchashookworm,Trichinella,andToxocara are more likely to cause eosinophilia


Rare causes of eosinophilia in children include connective tissue disorders, malignancies, and immunodeficiencies. Eosinophilic granulomatosis with polyangiitis presents with chronic sinusitis, refractory asthma, and moderate to severe eosinophilia.

Systemic lupus erythematosus and disorders with inflammatory arthritis can cause eosinophilia and should be considered when symptoms suggest rheumatologic disease. Eosinophilia occurs in association with lymphoid and myeloid malignancies as well as with solid tumors and can be seen after stem cell transplant.

Primary immunodeficiency syndromes should be suspected in a young infant with eosinophilia and recurrent or unusual infection or early, severe eczema.

How to evaluate?

Mild eosinophilia occurs frequently in children, is often an incidental finding, and is usually transient and clinically unimportant.

Persistent hypereosinophilia is less common and should be evaluated to identify conditions that can be treated and uncover and mitigate ongoing tissue damage.

Because the degree of eosinophilia may not ref lect the extent of tissue involvement, even mild eosinophilia should be noted and monitored.

All children with eosinophilia should undergo a thorough history and physical examination, looking for the etiology and evidence of tissue involvement. History should assess risk factors for parasitic infection and include a detailed drug histor

What are the red flags?

Red flags prompting urgent evaluation or referral include acute onset of fever, adenopathy, organomegaly, or evidence of organ dysfunction.

In the absence of these red f lags, mild and moderate eosinophilia can generally be managed with periodic monitoring

What is the treatment?

Therapy is directed at treating the underlying condition when identified. Because parasites are a common cause of eosinophilia in children,empirical treatment is often offered


Hospitalization is warranted for children with an extremely elevated AEC ($20,000/mL [$20×109/L]) and those with findings suggestive of cardiac, neurologic, or pulmonary dysfunction.

Systemic corticosteroids may be needed to treat acute organ dysfunction. Prognosis depends on the etiology as well as the degree of organ involvement.

Mild eosinophilia :rpt AEC after 3-6months

Mod eosinophilia: rpt AEC after 1 month

Severe eosinophilia: perform lab tests,look for organ dysfunction

What are the basic lab testing?


Basic laboratory testing: complete blood cell count with differential cell count and peripheral smear, tests of liver and renal function, urinalysis, stool/serology for parasites. Consider serum immunoglobulin E, electrocardiography, chest radiography.

About Dr. Jayaprakash

Asst. Prof. of Pediatrics, ICH. Institute of Child Health. Gov. Medical College Kottayam. Kerala, India.

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