Hypereosinophilia (eosinophils > 0.5 G/L)

• Hospital admission without waiting for the aetiological work-up (cardiac, respiratory, central neurological involvement or thrombosis).
• Before any corticosteroid therapy, take a strongyloidiasis serology.

Laboratory tests

• FBC with differential count (repeat)
• HIV serology (if risk factor)if neededRisk factor for HIV infection, rarer cause of eosinophilia between 0.5 and 1.5 G/L ^[2].
• Stool parasitology (if persistent without obvious cause, digestive symptoms or passage of proglottids)if neededPersistence without obvious cause, digestive symptoms or passage of proglottids: Taenia and Diphyllobothrium are diagnosed by stool parasitology (EPS) ^[2].
• Blood filmif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• CRPif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• Serum creatinineif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• ASTif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• ALTif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• GGTif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• Alkaline phosphataseif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• Bilirubinif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• Serum calciumif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].
• LDHif needednon-French guidelineThe British guideline (BSH, 2017, grade 1C) asks for this baseline work-up, with vitamin B12, for any eosinophilia ^[3]; the Scottish NHS Lothian guide limits it to FBC, blood film, CRP, renal and liver function, LDH and 3 stool parasitology tests (EPS) ^[6]. The PNDS does not provide for it between 0.5 and 1.5 G/L and accepts adding nothing when there is an obvious atopic context ^[2].

Laboratory tests

• FBC with blood film (repeat)
• Serum electrolytes
• Serum creatinine
• AST
• ALT
• GGT
• Alkaline phosphatase
• Bilirubin
• LDH
• Creatine kinase (CK)
• Serum calcium
• Serum phosphate
• Troponin, NT-proBNP
• Serum protein electrophoresis
• Serum tryptase
• Vitamin B12
• Total IgE
• CRP
• HIV serology
• Toxocariasis serology
• Stool parasitology
• Search for Strongyloides larvae in stool (Baermann) (if strongyloidiasis suspected)if neededSuspected strongyloidiasis, to be considered first after a stay in the tropics, even long ago ^[2].
• Strongyloidiasis serology (stay in a tropical area, or before corticosteroid therapy)if neededStay in the tropics, even long ago ^[2]; before any corticosteroid therapy, to exclude strongyloidiasis (risk of disseminated strongyloidiasis) ^[1,2].
• Fascioliasis serology (consumption of watercress or raw vegetables potentially contaminated)if neededSuggestive exposure: eating watercress or raw vegetables ^[2].
• Trichinellosis serology (myalgia, game or undercooked pork or horse meat)if neededSuggestive exposure: undercooked game, pork or horse meat; myalgia ^[2].
• ANCA (asthma, signs of vasculitis)if neededAsthma with hypereosinophilia: consider eosinophilic granulomatosis with polyangiitis (ANCA in 30 to 40%) ^[2].
• Antinuclear antibodies (ANA)if needednon-French guidelineThe British guideline (BSH, 2017) asks for them when a connective tissue disease is suspected ^[3]. The PNDS cites anti-CCP in inflammatory joint involvement, without including them in the minimal work-up ^[2].
• Anti-CCP antibodiesif needednon-French guidelineThe British guideline (BSH, 2017) asks for them when a connective tissue disease is suspected ^[3]. The PNDS cites anti-CCP in inflammatory joint involvement, without including them in the minimal work-up ^[2].
• IgA anti-tissue transglutaminase antibodies (tTG-IgA) (if diarrhoea or digestive signs)if needednon-French guidelineThe British guideline (BSH, 2017) includes coeliac disease serology when a digestive cause is suspected ^[3]. The PNDS reminds clinicians not to overlook this disease when there are digestive signs, without including it in the minimal work-up ^[2].

Imaging

• CT of chest, abdomen and pelvis; ECG and echocardiography if hypereosinophilia persists without cause.

Laboratory tests

• FBC with blood film
• Bilharziasis (schistosomiasis) serology
• Strongyloidiasis serology (strongyloidosis)
• Toxocariasis serology (if eosinophils > 1.5 G/L)if neededEosinophils > 1.5 G/L: complete with the work-up in the previous tab, which includes toxocariasis serology ^[2].
• HIV serology (if not done)if neededRoutine in hypereosinophilia > 1.5 G/L ^[2]; unnecessary if already done.
• HTLV-1 serology (origin or stay: Japan, Caribbean, sub-Saharan Africa)if neededOrigin from or stay in Japan, the Caribbean or sub-Saharan Africa ^[2].
• Filariasis serology and search for daytime microfilaraemia (origin in forested Central Africa, before any ivermectin)if neededPerson from forested Central Africa, before any ivermectin: if positive, no immediate treatment and infectious diseases advice (risk of severe effects in loiasis) ^[8].

Stool and urine

• Stool parasitology: 3 samples a few days apart
• Search for Strongyloides larvae in stool (Baermann)if neededSuspected strongyloidiasis, to be considered first after a stay in the tropics, even long ago ^[2].
• Urine parasitology (origin or stay in a schistosomiasis-endemic area): complete morning void or 24-hour urineif neededOrigin from or stay in a schistosomiasis-endemic area: test recommended in a migrant with eosinophilia ^[8].