Chapter 44 - Treatment of eosinophilic and hypereosinophilic disorders

Abstract

This chapter introduces an approach to the management of eosinophilic and hypereosinophilic disorders. Management of eosinophilic disorders, in general, depends on the severity of peripheral eosinophilia and whether eosinophilia is secondary to other conditions or is a primary condition due to the clonal expansion of eosinophils in the bone marrow. Objectives of treatment include managing and preventing organ damage, halting the progression of the disease, improving signs and symptoms, managing complications, and lowering the burden of absolute eosinophil count. Secondary causes of peripheral eosinophilia include infections, most commonly parasitic infestations, allergic and atopic disorders and related conditions, medications, malignancies, autoimmune, endocrine disorders, and other miscellaneous conditions. In these conditions, management should be focused on the treatment of the underlying condition or disorder. Parasitic infestations being the most common cause of eosinophilia worldwide require treatment of helminthic or other parasitic infestations. Atopic disorders and allergic reactions should be treated accordingly. Reaction to medications with a wide range of symptom severity is another common cause of secondary eosinophilia, in which the culprit medication should be removed. Primary eosinophilic disorders are those in which no such underlying etiology can be identified and are categorized as hypereosinophilic syndromes (HES). Identifying the molecular basis of HES is extremely important, as there are different considerations for the treatment of lymphocytic versus myeloproliferative variant HES. While tyrosine kinase inhibitors are considered the first-line treatment for myeloproliferative HES, steroids and steroid-sparing agents including monoclonal antibodies are considered the treatment of choice for lymphocytic variant HES. Special considerations for treatment should be given such as when there are cardiac, pulmonary, neurological, and mucocutaneous manifestations.