Why do dengue symptoms sometimes worsen on the 3rd to 5th day?

By Rebecca L. Castillo, MD

Answer:
Dengue has a “critical phase” around Day 3 to Day 5, when fever may go down but the risk of complications goes up. This is when plasma leakage, dehydration, and bleeding may occur. Warning signs include:

• Severe abdominal pain
• Persistent vomiting
• Sudden weakness or restlessness
• Bleeding gums or nose
• Very low platelet count

If any of these appear, bring the patient to the hospital immediately. Early hydration and monitoring prevent severe dengue.