From the Guidelines
Eosinophilia is most commonly caused by allergic disorders, parasitic infections, and certain medications, and the underlying cause should be addressed to guide treatment. The causes of eosinophilia can be broadly categorized into several groups, including:
- Allergic disorders such as asthma, hay fever, drug allergies, and atopic dermatitis, which are the most common cause of eosinophilia, occurring in about 80% of cases 1
- Parasitic infections, particularly those involving tissue-invasive helminths like Strongyloides, Ascaris, hookworm, and Schistosoma, which are the second most common cause of eosinophilia 1
- Certain medications, including antibiotics (especially penicillins and cephalosporins), NSAIDs, allopurinol, and phenytoin, which can trigger eosinophilia 1
- Autoimmune and inflammatory conditions, such as eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome), inflammatory bowel disease, and certain connective tissue diseases, which may also cause eosinophilia 1
- Hematologic disorders, including hypereosinophilic syndrome, mastocytosis, and some lymphomas and leukemias, which can lead to elevated eosinophil counts 1
- Pulmonary conditions, such as eosinophilic pneumonia, and some solid tumors, which may also be responsible for eosinophilia 1
When evaluating eosinophilia, it's essential to consider the patient's travel history, medication use, and presence of allergic symptoms to determine the underlying cause, as treatment depends on addressing the specific etiology rather than the eosinophilia itself 1.
Some key points to consider in the diagnosis and management of eosinophilia include:
- Accurate diagnosis of the underlying cause of eosinophilia is essential to establish the appropriate treatment plan 1
- Concentrated stool microscopy and strongyloides serology should be performed on all patients with eosinophilia, regardless of geographic exposure 1
- Empirical treatment with an antihelminthic agent such as albendazole may be considered in patients with eosinophilia and negative stool microscopy 1
- Non-infectious causes of eosinophilia, such as drugs, atopy, and allergy, should be considered, particularly if the eosinophilia is persistent 1
- Eosinophilia can be a feature of various diseases, including eosinophilic esophagitis, hypereosinophilic syndrome, and certain hematologic disorders 1
Overall, the management of eosinophilia requires a comprehensive approach that takes into account the underlying cause, the patient's medical history, and the presence of any underlying conditions that may be contributing to the eosinophilia.
From the Research
Causes of Eosinophilia
Eosinophilia can be caused by a variety of diseases, including:
- Allergies
- Autoimmune diseases
- Vasculitides
- Dermatoses
- Malignancies
- Drug-induced side effects
- Parasitic and non-parasitic infections 2, 3, 4, 5
Parasitic Infections
Parasitic infections are a common cause of eosinophilia, particularly in patients returning from the tropics 2, 5. The extent of eosinophilia can provide information about the type of pathogen.
Non-Parasitic Infections
Non-parasitic causes of eosinophilia include:
- Cryptococcosis
- Endemic systemic mycoses (coccidioidomycosis, histoplasmosis)
- Invasive mould infections (Aspergillus fumigatus, Mucor spp.) 2
Malignancies
Eosinophilia can also be associated with various types of cancer, including:
- Hematologic tumors (Hodgkin's disease, certain lymphomas)
- Solid tumors (colon, cervix, lung, breast, ovary) 6
Diagnostic Approach
The diagnostic approach to eosinophilia includes: