SynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyReferences

View all Images (7)

Hypereosinophilic syndrome in Adult
Other Resources UpToDate PubMed

Hypereosinophilic syndrome in Adult

Contributors: Tyler Werbel MD, Ryan Fan BA, Jeffrey M. Cohen MD, Susan Burgin MD, Nina Haghi MD, Paritosh Prasad MD
Other Resources UpToDate PubMed


Hypereosinophilic syndrome (HES) describes a group of disorders characterized by a persistent proliferation of eosinophils that infiltrate multiple organs, causing tissue damage. It can be primary (ie, neoplastic), secondary (ie, reactive), or idiopathic, as outlined below.

The 3 diagnostic criteria are:
  1. Peripheral hypereosinophilia (HE) (> 1.5 x 109/L) on 2 occasions separated in time by 4 weeks with or without marked tissue eosinophilia
  2. HE-related organ damage or dysfunction:
    • Greater than 20% eosinophils as compared to all nucleated cells on bone marrow section
    • Extensive tissue infiltration by eosinophils as determined by pathologist
    • Significant deposition of eosinophil granule proteins in tissue in absence of major tissue infiltration with eosinophils
  3. Absence of another explanation for the organ damage
The term HES is applied regardless of the etiology, but it is subclassified as:
  • Primary HES – Monoclonal HE due to an underlying stem cell, myeloid, or eosinophilic neoplasm.
  • Secondary HES – Polyclonal HE due to an overproduction of eosinophilopoietic cytokines. Potential causes include allergic disorders, malignancy, parasitic infection, and drug reactions.
  • Idiopathic HES – The underlying cause of the HE is unknown.
  • T-cell lymphocytic HES is associated with abnormal clones of T-cells producing Th-2 cytokines, specifically interleukin-5, which results in increased eosinophil production. These patients are at increased risk of developing lymphoma.
  • Myeloproliferative HES is most commonly associated with the FIP1L1-PDGFRA fusion gene (encoding an activated tyrosine kinase), as well other chromosomal aberrations. This genetic mutation is found in various forms of myeloproliferative HES including eosinophilic leukemia.
  • Familial HES is associated with autosomal dominant inheritance and linkage to chromosome 5q31-33. Although most affected individuals are asymptomatic, fatal progression of the disease has occurred.
  • Other eosinophilic disorders: eosinophilic vasculitis; eosinophilic gastritis; episodic angioedema with eosinophilia (also known as Gleich syndrome); nodules, eosinophilia, rheumatism, dermatitis, and swelling (NERDS) syndrome; etc.
The International Hypereosinophilic Syndromes Working Group has further adjusted the classification system for eosinophilic disorders. They describe 6 variants of hypereosinophilic syndrome.
  1. Myeloproliferative variant (3 types):
    • PDGFRA-associated HES (FIP1L1-PDGFRA: interstitial deletion of chromosome 4q12).
    • Unknown etiology (FIP1L1-PDGFRA negative) associated HES.
    • Chronic eosinophilic leukemia (CEL) characterized by cytogenetic abnormalities and/or peripheral blasts.
    • Findings associated with the myeloproliferative variant are hepatosplenomegaly, anemia, thrombopenia, bone marrow dysplasia or fibrosis, and elevated cobalamin levels.
  2. Lymphocytic variant: Associated with clonal proliferation of T-cells, and primarily characterized by skin disease. This follows a more benign course.
  3. Idiopathic / undefined variant not associated with chromosomal or clonal abnormalities.
  4. Overlap variant (organ-restricted eosinophilic disorders).
  5. Associated variant (eosinophilia in association with a defined diagnosis, for example, Churg-Strauss syndrome).
  6. Familial variant (familial history of documented persistent eosinophilia of unknown cause).
Worldwide frequency of HES is rare with an estimated prevalence of 0.32-6.3 per 100 000. Both sexes and all races / ethnicities may be affected. FIP1L1-PDGFRA-associated myeloproliferative HES is more common in males. Age of onset ranges from 20-50 (mean: 33 years). HES is especially rare in children and the elderly.

Morbidity and mortality from HES is variable. This condition may be quiescent or rapidly fatal from heart failure secondary to progressive restrictive cardiomyopathy. Poorer prognoses are associated with malignant transformation to eosinophilic leukemia, higher eosinophil counts, and cardiac or neurologic involvement.


D72.119 – Hypereosinophilic syndrome [HES], unspecified

414450004 – Idiopathic hypereosinophilic syndrome

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

  • Parasitic infections (eg, Strongyloidiasis)
  • Drug eruption general overview
  • Angiolymphoid hyperplasia with eosinophilia – Look for papules, plaques, and nodules in the head and neck region.
  • Eosinophilic granulomatosis with polyangiitis – Look for allergic rhinitis, asthma, peripheral neuropathy, and vasculitis.
  • Eosinophilic leukemia – Look for bone marrow sample with leukemic blast cells and eosinophilic differentiation.
  • Eosinophilia-myalgia syndrome – Look for flu-like and neurological symptoms and a history of L-tryptophan supplementation.
  • Eosinophilic cellulitis (Wells syndrome) – Look for bright-red to slate-blue papules, plaques, or wheals and "flame figures" on skin biopsy.
  • Eosinophilic fasciitis – Look for peau d'orange appearance to the skin and a history of strenuous exercise.
  • Ofuji disease (Ofuji disease) – Look for pruritic folliculitis in patients with human immunodeficiency virus (HIV).
  • Eosinophilic ulcer – Look for mucosal (usually oral) ulcers in areas of chronic trauma.
  • Kimura disease – Look for painless unilateral cervical lymphadenopathy in males of Asian descent.

Best Tests

Subscription Required

Management Pearls

Subscription Required


Subscription Required


Subscription Required

Last Reviewed:06/11/2022
Last Updated:03/31/2021
Copyright © 2024 VisualDx®. All rights reserved.
Hypereosinophilic syndrome in Adult
A medical illustration showing key findings of Hypereosinophilic syndrome : Abdominal pain, Altered mental state, Cough, Diarrhea, Fatigue, Nausea, Vomiting, IgE elevated, Lymphadenopathy, Arthralgia, Dyspnea, Pruritus, Wheezing, EOS increased, Hives
Clinical image of Hypereosinophilic syndrome - imageId=241116. Click to open in gallery.  caption: 'Widespread scaly erythematous papules (eczema) on the leg.'
Widespread scaly erythematous papules (eczema) on the leg.
Copyright © 2024 VisualDx®. All rights reserved.