Can a patient with elevated eosinophils, a history of potential mold exposure, and normal High-Resolution Computed Tomography (HRCT) scan, but no respiratory symptoms, be sent back to their Primary Care Physician (PCP) for further management?

Can You Send This Patient Back to PCP?

Yes, a patient with elevated eosinophils, potential mold exposure history, normal HRCT, and no respiratory symptoms can be appropriately managed by their primary care physician, provided you have excluded helminth infections and documented that eosinophilia is mild (<1.5 × 10⁹/L). 1

Risk Stratification Based on Eosinophil Count

Mild eosinophilia (0.5-1.5 × 10⁹/L) without symptoms or end-organ damage can be managed in primary care after appropriate initial workup. 1

• If eosinophilia is ≥1.5 × 10⁹/L and persists for more than 3 months after excluding/treating infectious causes, refer to hematology regardless of symptoms. 1, 2
• Any eosinophil count with evidence of end-organ damage (cardiac, pulmonary, neurologic) requires urgent specialist evaluation, not PCP referral. 3, 2

Essential Workup Before PCP Referral

You must exclude helminth infections before discharge, as these account for 19-80% of eosinophilia in returning travelers/migrants and can cause life-threatening complications if missed. 1, 3

Required Testing:

• Three separate concentrated stool specimens for ova and parasites 1
• Strongyloides serology - critical because this parasite can persist lifelong and cause fatal hyperinfection syndrome in immunocompromised patients 1, 3
• Schistosomiasis serology if any freshwater exposure in endemic areas (Africa, Southeast Asia, South America, Arabian peninsula) 1

Geographic Exposure Matters:

• Detailed travel history focusing on freshwater exposure, raw/undercooked meat consumption, and timing relative to eosinophilia onset 1, 3
• For West Africa exposure specifically, consider filarial serology 1

Why Normal HRCT and No Respiratory Symptoms Support PCP Management

Normal HRCT effectively excludes hypersensitivity pneumonitis and other eosinophilic lung diseases that would require pulmonary specialist management. 1

• HRCT is the diagnostic procedure of choice for bronchiectasis and small airways disease 1
• Absence of respiratory symptoms (cough, wheeze, dyspnea) makes conditions like tropical pulmonary eosinophilia, Loeffler's syndrome, and chronic eosinophilic pneumonia unlikely 1, 4
• Mold exposure alone without radiographic findings or symptoms does not warrant specialist pulmonary evaluation 1

What PCP Should Monitor

Provide clear guidance to the PCP on follow-up parameters:

• Recheck absolute eosinophil count in 3 months 1
• Return immediately if any symptoms develop: dysphagia, abdominal pain, rash, neurologic symptoms, cardiac symptoms, or respiratory symptoms 3, 2
• If eosinophilia persists ≥1.5 × 10⁹/L at 3 months, refer to hematology 1, 2

Common Pitfalls to Avoid

Do not assume normal eosinophil counts exclude helminth infection - many infected patients have normal counts, so testing should be based on exposure history, not eosinophil level alone. 1, 2

Do not send patient to PCP without completing helminth workup first - Strongyloides can remain asymptomatic for decades then cause fatal hyperinfection if patient becomes immunocompromised (steroids, chemotherapy, transplant). 1, 3

Do not ignore non-infectious causes in your differential - allergic disorders, medications, and atopy are the most common causes of mild eosinophilia in non-endemic areas. 1 Document medication review and allergy history in your referral note.

Beware cross-reactivity in helminth serology - low-level positive filarial serology can occur with strongyloidiasis; interpret results in clinical context. 1

When NOT to Send to PCP

• Eosinophil count ≥1.5 × 10⁹/L at any point 1, 2
• Any symptoms suggesting organ involvement (GI, cardiac, pulmonary, neurologic, dermatologic) 3, 2
• Positive helminth testing requiring specialized treatment 1, 3
• Immunocompromised or anticipated immunosuppression 1, 3