Is eosinopenia seen in typhoid fever?

Eosinopenia in Typhoid Fever

Yes, eosinopenia is commonly seen in typhoid fever and can be an important diagnostic clue when evaluating patients with fever, especially those with travel history to endemic regions. 1, 2, 3

Evidence for Eosinopenia in Typhoid

• Multiple studies have demonstrated a strong association between typhoid fever and eosinopenia:
  • A 2008 study found absolute eosinopenia in 76.9% of culture-proven typhoid cases 2
  • A 2013 study reported that typhoid patients consistently had low eosinophil counts 3
  • A 2014 study observed eosinopenia in 100% of patients with typhoid/paratyphoid infections 4

Clinical Significance of Eosinopenia in Typhoid

• Eosinopenia can be a valuable early diagnostic marker when evaluating febrile patients, particularly:

  • Returning travelers from endemic areas (especially South/Southeast Asia and Sub-Saharan Africa) 5
  • After excluding malaria as a cause of fever 3
  • When combined with other laboratory findings such as elevated liver transaminases 3, 6

• The UK guidelines for investigation of fever in returned travelers specifically mention lymphopenia and eosinopenia as common findings in typhoid fever 1

Diagnostic Algorithm When Suspecting Typhoid

1. Initial assessment:

   • Check complete blood count with differential
   • Look specifically for eosinopenia (absolute eosinophil count of 0%) 2
   • Evaluate for relative bradycardia (fever with inappropriately normal heart rate)
   • Check liver function tests (often elevated in typhoid) 3, 6

2. Confirmatory testing:

   • Blood cultures (gold standard) - obtain at least two sets prior to antibiotics 1
   • Consider serological tests like Widal or Typhidot (though less reliable) 6

Important Considerations

• While eosinopenia is common in typhoid, it is not pathognomonic and can be seen in other conditions:

  • Other bacterial infections
  • Acute stress responses
  • Steroid use

• Eosinopenia contrasts with the eosinophilia typically seen in many parasitic infections, which can help in differential diagnosis 1, 7

• The absence of eosinophils in a febrile patient with appropriate travel history should raise suspicion for typhoid fever, especially when combined with:

  • Relative bradycardia
  • Hepatosplenomegaly
  • Slow defervescence despite antibiotics 5

Treatment Implications

• When typhoid is suspected based on clinical presentation including eosinopenia:
  • Start empiric treatment while awaiting culture results
  • Consider resistance patterns based on travel history
  • Third-generation cephalosporins or azithromycin are often preferred due to increasing fluoroquinolone resistance 3, 6

By recognizing the association between eosinopenia and typhoid fever, clinicians can more rapidly identify and appropriately treat this potentially serious infection, particularly in returning travelers from endemic regions.