Eosinophilia - Causes and Symptoms

Definition

Eosinophilia is a condition characterized by an increase in the number of eosinophils in peripheral blood, with values greater than 0.6x109 / l.

In particular, we usually talk about:

Eosinophilia Mild: when the number of eosinophils is between 0.5 and 1.5x109 / l.
Eosinophilia Moderate: if it varies between 1.5 and 5.0x109 / l.
Grave Eosinophilia: when it exceeds 5.0x109 / l.

Eosinophilia can be:

primary : clonal proliferation of eosinophils is associated with haematological disorders, such as leukemia and myeloproliferative diseases;
secondary to numerous other non-hematological diseases;
or idiopathic : if the triggered causes cannot be identified.

Eosinophilia is most frequently found in the context of allergic diseases - especially respiratory or dermatological diseases, such as asthma, allergic rhinitis, urticaria, atopic dermatitis - angioneurotic edema and reaction to drugs associated with increased IgE.

Other common causes of eosinophilia include bacterial infections (eg tuberculosis), mycosis (eg aspergillosis) and parasitosis involving organs (eg, teniasis) or tissues (eg, trichinosis and filariasis).

Among the infectious diseases associated with the increase in eosinophils also include brucellosis, cat scratch disease, infectious mononucleosis, scarlet fever, cysticercosis, echinococcosis and schistosomiasis.

An eosinophilic reaction is frequent also in the presence of hematological or solid, benign or malignant tumors. Among the neoplastic diseases, Hodgkin's lymphoma can cause marked eosinophilia. Other tumors that show this alteration are acute leukemias, chronic myeloproliferative syndromes and myelodysplastic syndromes with eosinophilic differentiation. Ovarian cancer is the solid tumor most commonly associated with eosinophilia, but this alteration may also occur in the presence of gastric and pulmonary neoplasms.

The increase in the number of circulating eosinophils in the blood can also occur in the context of skin diseases, such as eczema, psoriasis, dermatitis herpetiformis, pemphigus vulgaris and pityriasis rubra. Eosinophilia can result from connective tissue diseases and autoimmune disorders: rheumatoid arthritis, systemic lupus erythematosus, scleroderma, dermatomyositis, Sjögren's syndrome, Wegener's granulomatosis, Churg-Strauss syndrome (eosinophilic vasculitis, neuropathy and asthma), eosinophilic pneumonia ( Löffler syndrome) and eosinophilic fasciitis (Schulman syndrome).

This manifestation is also found in states of congenital immunodeficiency (Wiskott-Aldrich syndrome, IgA deficiency and hyper-IgE syndrome).

Eosinophilia is also associated with kidney diseases (pyelonephritis), sarcoidosis, cholestatic hepatopathies, Addison's disease and adrenal insufficiency.

An eosinophilic reaction may occur due to certain drugs (nitrofurantoin, phenylidantoin, sulfonamides, aspirin and IL-2), use of l-tryptophan, radiotherapy, post transplantation of marrow, post-splenectomy and peritoneal dialysis.