Clinical Suspicion of Dengue Fever
Dengue fever should be suspected in patients presenting with fever accompanied by at least one of the following symptoms: headache, retro-orbital pain, myalgia, arthralgia, rash, nausea, vomiting, or leukopenia, especially if they have recently traveled to or reside in endemic areas. 1, 2
Key Clinical Features to Suspect Dengue Fever
Essential Symptoms
- Fever: Typically high-grade (38.5-40°C), acute onset
- Headache: Often severe
- Retro-orbital pain: Pain behind the eyes, worsened by eye movement
- Myalgia and arthralgia: Severe muscle and joint pain (hence the name "breakbone fever")
- Rash: Maculopapular or petechial, typically appearing 3-4 days after fever onset
Additional Common Symptoms
- Nausea and vomiting
- Mild bleeding manifestations (epistaxis, gingival bleeding, petechiae)
- Leukopenia (low white blood cell count)
- Pain behind the eyes
- Positive tourniquet test
Epidemiological Context
- Recent travel to or residence in endemic areas (tropical and subtropical regions, particularly Asia and South America)
- Local outbreaks or seasonal epidemics
- History of mosquito bites (especially daytime bites)
Warning Signs for Severe Dengue
Monitor closely for progression to severe disease if any of these warning signs develop:
- Abdominal pain or tenderness
- Persistent vomiting
- Clinical fluid accumulation (pleural effusion, ascites)
- Mucosal bleeding
- Lethargy or restlessness
- Liver enlargement
- Laboratory findings: increasing hematocrit with rapid decrease in platelet count 2
Differential Diagnosis
Consider other infectious etiologies including:
- Chikungunya
- Malaria
- Rubella
- Measles
- Hepatitis A
- Parvovirus
- Adenovirus
- Enterovirus
- Leptospirosis
- Rickettsiosis
- Group A streptococcal infections 1
Laboratory Findings
While clinical suspicion is based on symptoms, these laboratory findings support the diagnosis:
- Thrombocytopenia (platelet count <100,000/mm³)
- Leukopenia
- Elevated hematocrit (indicating hemoconcentration)
- Elevated liver enzymes
Timing of Symptom Presentation
- Early phase (0-3 days): Fever, general symptoms
- Critical phase (3-7 days): Defervescence period when warning signs may appear
- Recovery phase (>7 days): Improvement of symptoms, possible itchy rash and bradycardia
Special Considerations
- Pregnant women require closer monitoring due to higher risk of complications 2
- Children may present with less specific symptoms and require careful assessment 2
- Secondary infections (previous exposure to dengue) carry higher risk of severe disease 2
Common Pitfalls in Diagnosis
- Mistaking dengue for other viral illnesses or "flu"
- Failing to obtain travel history
- Missing warning signs of progression to severe disease
- Overlooking the possibility of dengue in non-endemic areas in travelers
Early recognition of dengue fever is crucial for appropriate management and prevention of complications. The diagnosis should be confirmed with laboratory testing (NS1 antigen detection, RT-PCR, or serological tests) depending on the timing of presentation relative to symptom onset.