Last updated: Tuesday, 30, November, 2010
CausesAppropriate Tests

Mild eosinophilia is a common finding, particularly in children, and is often transient.

Review clinical findings; follow up FBC, differential WCC, blood film.

See Table 4 Reference intervals for leucocyte differential counts

For persistent or marked eosinophilia, CRP, immunoglobulin E may be helpful.

Drug reactions
  • Penicillin
  • Sulphonamides
  • Gold salts
  • Carbamazepine
Atopic disease

Marked eosinophilia can occur.

See Food intolerance/allergy.

Skin disorders Skin biopsy with IH, if indicated.

Eosinophilic granuloma

Parasitic infection (with tissue invasion)

  • Toxocara sp
  • Ascaris
  • Strongyloides stercoralis
  • Schistosomiasis
  • Trichiaos filariasis
  • Cystercercosis
  • Echinococous

Faeces - ova, cysts and parasites.

Toxocara antibodies.

Harada culture on faeces - consult pathologist.

Strongyloides sp antibodies; Harada culture. This is important to identify in patients on steroids or immunosuppression, who have lived in tropical countries, since they are at risk of hyperinfection syndrome.

Hypereosinophilic syndromes

Usually defined as a marked eosinophilia (>1.5 x 109/L) for more than 6 months in the presence of a consistent clinical picture.

Biopsy of appropriate tissue, if indicated. 

  • Loeffler’s syndrome

Eosinophilic leukaemia

Bone marrow aspiration and trephine biopsy.

Pulmonary infiltration with eosinophilia (PIE) including

  • Allergic bronchopulmonary aspergillosis
  • Cocaine pneumonitus

Skin prick allergen testing especially antigens of Aspergillus sp. Aspergillus precipitins; immunoglobulin E.

See under Aspergillosis.

Vasculitis, especially

  • Churg-Strauss syndrome