Eosinophilia Symptoms by Organ System: A Clinical Guide

Eosinophilia (>500 cells/µL) manifests diversely depending on etiology (allergic, parasitic, neoplastic, autoimmune) and tissue infiltration:

Organ-System Presentation

• Skin: Urticaria, angioedema, atopic dermatitis, eosinophilic cellulitis (Wells syndrome), pemphigoid.
• Respiratory: Asthma (eosinophilic phenotype), allergic rhinitis, eosinophilic pneumonia (acute/chronic), ABPA, EGPA (Churg-Strauss).
• Gastrointestinal: Eosinophilic esophagitis, gastritis, gastroenteritis, colitis—dysphagia, pain, diarrhea, malabsorption.
• Cardiac: Eosinophilic myocarditis (Loeffler endocarditis) → HF, arrhythmia, thromboembolism.
• Neurologic: Peripheral neuropathy, encephalitis, cognitive changes (hypereosinophilic syndrome).
• Hematologic: Anemia of chronic disease, thrombocytopenia, lymphadenopathy, splenomegaly.
• Constitutional: Fever, weight loss, fatigue, night sweats (especially neoplastic/parasitic).

Diagnostic Framework

1. Confirm absolute eosinophil count (AEC); grade: mild (500–1500), moderate (1500–5000), severe (>5000).
2. History: travel, medications, atopy, exposures.
3. Targeted workup: stool O&P, IgE, specific IgE, ANCA, FIP1L1-PDGFRA, T-cell clonality, imaging.
4. Tissue biopsy if organ involvement suspected.

Key Principle

Eosinophilia is a sign, not a diagnosis. Treat the underlying cause (helminths, allergy, malignancy, drug reaction, HES). Corticosteroids reduce eosinophils broadly but mask etiology if given prematurely.