When is it appropriate to refer a patient with eosinophilia for further specialist evaluation?

Referral for specialist evaluation in patients with eosinophilia is appropriate when there is suspicion of an underlying serious condition such as haematological malignancy (e.g., leukaemia or lymphoma), especially if accompanied by systemic symptoms like night sweats, unexplained lymphadenopathy, splenomegaly, pruritus, or weight loss. In such cases, urgent referral for specialist assessment within 48 hours is recommended to exclude or confirm malignancy.

Additionally, referral is appropriate if eosinophilia is associated with confirmed or suspected allergic diseases that are not responding to standard management, such as severe or persistent atopic eczema with suspected multiple or cross-reactive food allergies, or if there is faltering growth combined with gastrointestinal symptoms suggestive of food allergy. In these scenarios, specialist allergy or dermatology input is warranted.

In asthma, elevated eosinophil counts may support diagnosis and management, but referral is generally based on clinical severity and response to treatment rather than eosinophilia alone.