From the Guidelines
Slightly elevated eosinophils on a CBC are most commonly caused by allergic reactions, parasitic infections, skin conditions, autoimmune disorders, and certain medications, as evidenced by recent studies 1. When considering the potential causes of slightly elevated eosinophils, it is essential to take into account the patient's medical history, symptoms, and lifestyle. Allergic reactions, including seasonal allergies, food allergies, asthma, or drug reactions, are common causes of eosinophilia 1. Parasitic infections, such as intestinal worms, are another significant cause, especially in people who have traveled to or lived in areas where these infections are common 1. Certain skin conditions like eczema and psoriasis can also trigger eosinophil elevation 1. Autoimmune disorders, including rheumatoid arthritis, lupus, and inflammatory bowel disease, may increase eosinophil counts 1. Some medications, particularly antibiotics, NSAIDs, and certain psychiatric drugs, can cause drug-induced eosinophilia 1. Less commonly, adrenal insufficiency, certain cancers (especially lymphomas and leukemias), and rare conditions like eosinophilic esophagitis or hypereosinophilic syndrome may be responsible 1. Key factors to consider when evaluating slightly elevated eosinophils include:
- Medical history: presence of allergies, parasitic infections, skin conditions, or autoimmune disorders
- Symptoms: presence of symptoms such as dysphagia, food impaction, or abdominal discomfort
- Lifestyle: travel history, exposure to potential allergens or parasites
- Medications: current or recent use of medications that may cause eosinophilia It is crucial to note that mild elevations are often transient and may not require treatment, but persistent elevation warrants further investigation to identify the underlying cause, as recommended by recent guidelines 1. The body produces more eosinophils in response to these conditions because these white blood cells play a key role in fighting parasites and participating in allergic and inflammatory responses 1.
From the Research
Causes of Elevated Eosinophils
Eosinophils can be slightly elevated on a Complete Blood Count (CBC) due to various reasons, including:
- Parasitic diseases 2
- Allergic diseases, such as allergic drug eruption, urticaria, allergic contact dermatitis, atopic dermatitis, and eczema 2, 3
- Autoimmune diseases, including bullous pemphigoid 3
- Connective tissue diseases and rheumatologic diseases 2
- Primary eosinophilia, such as hypereosinophilic syndrome 2
- Malignant states 2
- Parasitic infestations and arthropod bites 3
- Eosinophilic skin diseases, including eosinophilic cellulitis, granuloma faciale, eosinophilic pustular folliculitis, recurrent cutaneous eosinophilic vasculitis, and eosinophilic fasciitis 3
- Gastrointestinal disorders, such as eosinophilic gastrointestinal diseases, celiac disease, inflammatory bowel diseases, and parasitic infections 4
Eosinophil Functions
Eosinophils perform various tasks, including:
- Involvement in inflammatory reactions associated with innate immune defense against parasitic infections 5, 6
- Participation in pathological processes in response to allergens 5, 6
- Playing a crucial role in the generation and maintenance of adaptive immune responses, including the survival of plasma cells in the bone marrow and the maintenance of mucosal IgA plasma cells 5
- Antigen presentation and immunoregulation through the release of cytokines 6