Definition
Eosinophilia is defined as an elevation of the eosinophil count above 0.4 x109/L. The initial step in the evaluation of eosinophilia is to rule out reactive (secondary) causes- please see the Primary Care Management page.
The most common causes of eosinophilia are allergy, eczema/asthma, drug-induced and parasitic infections.
After reactive causes have been ruled out, the patient may be referred to Haematology for investigation of clonal eosinophilia.
C.M & L.W 26-06-23
Who to refer:
Patients with significant persistent eosinophilia (≥ 1.5 x 109/L) without obvious underlying reactive cause.
Who not to refer:
- Reactive eosinophilia – the patient may require assessment by other specialties, e.g. Rheumatology, Dermatology, Infectious Disease, Respiratory Medicine depending on symptoms
- Patients with persistent unexplained mild to moderate eosinophilia (0.4-1.4 x109/L) can be given a diagnosis of idiopathic eosinophilia once secondary causes have been excluded.
Please see Primary Care Management for initial investigative approaches.
How to refer:
SCI Gateway to the Department of Haematology WGH or SJH.
Primary care investigations
- Look for underlying causes such as
- Allergic disorders such as atopic eczema, asthma, hay fever
- Drugs
- Parasites
- Vasculitis (e.g. eosinophilic granulomatosis with polyangiitis)
- Allergic bronchopulmonary aspergillosis
- Malignancy
- Hodgkin lymphoma.
Investigations:
- FBC + film
- CRP
- U&E, LFT, LDH
- Stools x 3 for ova, cysts and parasites
- Repeat FBC at 3 months.
