5. APPROACH
History —
Constitutional: Fever, night sweats, unintentional weight loss, fatigue
Cutaneous: Eczema, pruritus, urticaria, angioedema, rash, ulcers
Cardiac: Dyspnea, chest pain, palpitations, symptoms of heart failure
Respiratory: Nasal/sinus symptoms, wheezing, cough, chest
congestion
Gastrointestinal: Weight loss, abdominal pain, dysphagia, nausea,
vomiting, diarrhea, food intolerance, changes in stools
Nervous system: Transient ischemic attack, cerebrovascular accident,
behavioral changes, confusion, balance problems, memory loss, change
in vision, numbness, weakness, pain
Other: Including symptoms attributable to lymphadenopathy or
hepatosplenomegaly (ie, new abdominal or chest discomfort, early
satiety), ocular findings, genitourinary complaints, myalgia, arthralgia,
and anaphylaxis
6. Medications – Current and past medications should be reviewed in
detail, since eosinophilia can be caused by almost any prescription or
nonprescription drug, herbal remedy, or dietary supplement
Dietary history should explore ingestion of raw or undercooked fish or
shellfish, meat, and vegetables as potential sources of parasitic infection
(eg, Trichinella, Toxocara, Paragonimus). Food allergies and self-
imposed dietary restrictions should also be explored.
Other exposures – May include infectious exposures including:
- Occupation (eg, Strongyloides infection in miners, ascariasis in
slaughterhouse workers)
- Recreational activities (eg, schistosomiasis in river rafters in endemic
areas)
- Travel or residence in countries that may be associated with infectious
exposures
Family history may be informative in rare cases of familial hematologic
7. Physical examination —
Complete skin examination and evaluation for lymphadenopathy
and hepatosplenomegaly.
Relevant physical findings include, rash, nasal/sinus findings,
signs of cardiac and/or respiratory abnormalities,
lymphadenopathy, hepatomegaly/splenomegaly, or neurologic
findings.
8. Laboratory and diagnostic tests
Routine laboratory tests —
complete blood count (CBC) with differential count
chemistry panel that includes electrolytes and liver function tests
Blood smear —to assess eosinophil morphology and detect other
hematologic abnormalities
Tests for selected patients —
Cardiac troponin –in patients with AEC ≥1500/microL, cardiac
symptoms, or suggestive abnormalities on physical examination (eg,
dyspnea, fatigue, palpitations, heart murmur, cardiac dysrhythmia).
Vitamin B12 and tryptase – in patients with AEC ≥1500/microL,
abnormal blood smear, anemia or thrombocytopenia, splenomegaly, or
symptoms consistent with systemic mastocytosis (eg, urticaria,
anaphylaxis, flushing, or abdominal symptoms)
9. Imaging – a chest radiograph for patients with respiratory
symptoms (eg, dyspnea, cough, wheezing, rhinosinusitis).
atients with an unexplained infiltrate or AEC ≥1500/microL, we
suggest high resolution computed tomography (CT) and
pulmonary function tests.
Infectious evaluation – is greater in patients whose travel or
residence suggests possible exposure to parasites or other
infections
10. CLINICAL SCENARIOS
Suspected hematologic disorder — A hematologic cause should be
considered if findings from the initial evaluation do not persuasively point
toward a clear secondary cause of eosinophilia or to a characteristic
clinical syndrome (eg, eosinophilic esophagitis, episodic angioedema
with eosinophilia, eosinophilic granulomatosis with polyangiitis)
Findings that should prompt testing for a hematologic disorder
Absolute eosinophil count (AEC) ≥1500/microL
Dysplastic eosinophils or leukemic blasts
Unexplained anemia, neutropenia, polycythemia, or thrombocytopenia
Elevated serum B12 or tryptase levels
Lymphocytosis (≥4000/microL)
Unexplained lymphadenopathy, splenomegaly, or constitutional
symptoms
Resistance of eosinophilia to glucocorticoid therapy
11. Constitutional symptoms —
Possible causes of eosinophilia in association with constitutional
symptoms include
- Infectious, especially in the setting of appropriate travel or residency, or if
associated with gastrointestinal, respiratory, cutaneous, or other
symptoms.
- medications, especially if associated with appropriate exposure and/or
other manifestations
- Neoplastic disorders (eg, hypereosinophilic syndromes, lymphoma, solid
tumors) should be considered in patients with lymphadenopathy,
hepatomegaly, splenomegaly; anemia, thrombocytopenia
- Eosinophilic granulomatosis with polyangiitis (EGPA, formerly called
Churg-Strauss) should be considered, especially if associated with
asthma, sinusitis, dyspnea, and/or mononeuritis multiplex.
- Autoimmune syndromes or immune dysfunction associated with
eosinophilia
12. Gastrointestinal — Eosinophilia associated with diarrhea,
abdominal pain, anorexia, or other gastrointestinal symptoms may
be due to infectious, autoimmune, or other causes.
Respiratory —Eosinophilia with cough, dyspnea, wheezing,
chronic nasal complaints, abnormal chest X-ray or computed
tomography (CT), and/or pulmonary emboli may be associated with
diverse causes, including asthma/allergies, medications,
autoimmune illnesses, infections, EGPA, and idiopathic conditions
Cutaneous manifestations (eg, rash, pruritus, dermographism,
erythroderma, thickening) can be seen in association with almost
any cause of eosinophilia (Eg atopy, medications, parasitic
infections, autoimmune/inflammatory conditions, HES and other
hematologic causes, primary immunodeficiencies)
