What Causes Eosinophilia?

Eosinophilia is a condition characterized by an elevated number of eosinophils, a type of white blood cell, in the peripheral blood. Eosinophilia can be caused by various underlying conditions, and the elevation of eosinophils may indicate an immune system response. Some common causes of eosinophilia include:

  • Allergic Reactions:
    • Allergic disorders, such as asthma, hay fever (allergic rhinitis), and atopic dermatitis, can lead to eosinophilia.
  • Parasitic Infections:
    • Helminth (worm) infections, such as intestinal parasites like roundworms or tapeworms, can trigger an immune response and result in eosinophilia.
  • Drug Reactions:
    • Certain medications can cause an allergic or hypersensitivity reaction, leading to eosinophilia. Examples include some antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and anticonvulsants.
  • Autoimmune Diseases:
    • Autoimmune conditions, such as eosinophilic granulomatosis with polyangiitis (formerly known as Churg-Strauss syndrome) and systemic lupus erythematosus (SLE), may be associated with eosinophilia.
  • Hematologic Disorders:
    • Conditions affecting the bone marrow, such as eosinophilic leukemia or hypereosinophilic syndrome (HES), can lead to elevated eosinophil levels.
  • Eosinophilic Gastrointestinal Disorders:
    • Conditions like eosinophilic esophagitis, eosinophilic gastritis, or eosinophilic colitis involve inflammation of the gastrointestinal tract and may result in eosinophilia.
  • Respiratory Infections:
    • Certain respiratory infections, including fungal infections or certain viral infections, can cause eosinophilia.
  • Skin Conditions:
    • Eosinophilia may be associated with certain skin disorders, such as bullous pemphigoid, dermatitis herpetiformis, or eosinophilic cellulitis.
  • Malignancies:
    • Some cancers, particularly certain types of lymphomas and solid tumors, can lead to eosinophilia.
  • Idiopathic Hypereosinophilic Syndrome (HES):
    • In some cases, the cause of eosinophilia may not be clearly identified, and it is referred to as idiopathic HES.

It’s important to note that eosinophilia is a sign rather than a specific disease. Identifying the underlying cause is crucial for appropriate management. A healthcare professional may conduct a thorough medical history, physical examination, blood tests, imaging studies, and, if necessary, tissue biopsies to determine the cause of eosinophilia and guide treatment. Treatment often involves addressing the underlying condition contributing to the elevated eosinophil levels.