What are the warning signs of Dengue (Dengue hemorrhagic fever)?

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Last updated: February 26, 2025View editorial policy

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From the Guidelines

The warning signs of Dengue hemorrhagic fever include severe abdominal pain, persistent vomiting, bleeding from gums or nose, blood in vomit or stool, rapid breathing, fatigue, restlessness, and cold or clammy skin, which typically appear as the fever begins to subside (around days 3-7 of illness) and indicate potential plasma leakage, hemorrhage, or organ impairment. The clinical presentation of dengue varies from a mild febrile illness to dengue hemorrhagic fever (DHF) or dengue shock syndrome, with the latter two being rare in travelers 1. Classic dengue fever is characterized by a febrile illness associated with headache, retro-orbital pain, myalgia, arthralgia, and rash 1. Key warning signs that indicate severe dengue and require immediate medical attention include:

  • Severe abdominal pain
  • Persistent vomiting
  • Bleeding from gums or nose
  • Blood in vomit or stool
  • Rapid breathing
  • Fatigue
  • Restlessness
  • Cold or clammy skin These warning signs are critical, as severe dengue can progress rapidly and become life-threatening if not promptly treated. The underlying mechanism involves increased vascular permeability due to inflammatory mediators released during the immune response to the dengue virus, which can lead to plasma leakage, shock, and organ failure if not promptly treated. Patients should seek immediate medical care if any of these warning signs develop.

From the Research

Warning Signs of Dengue Hemorrhagic Fever

The warning signs of Dengue Hemorrhagic Fever (DHF) include:

  • Abdominal pain or tenderness 2, 3, 4
  • Persistent vomiting 2, 3, 5, 4
  • Mucosal bleeding 2, 3, 4
  • Lethargy 2, 3, 4
  • Hepatomegaly (liver enlargement) 2, 3, 4
  • Increasing hematocrit with decreasing platelets 2, 3, 4
  • Clinical fluid accumulation 2, 3, 4
  • Hematocrit increase 5
  • Platelet decrease 5

Specific Warning Signs

Specific warning signs that are highly specific for DHF or Severe Dengue (SD) include:

  • Persistent vomiting 2, 3
  • Hepatomegaly 2, 3
  • Hematocrit rise and rapid platelet drop 2
  • Clinical fluid accumulation 2, 3
  • Any 3 or 4 of the WHO warning signs 2

Other Warning Signs

Other warning signs that may indicate severe dengue include:

  • Hypothermia 6
  • Leukocytosis (high white blood cell count) 6
  • Bandemia (high band cell count) 6
  • Profound thrombocytopenia (low platelet count) 6
  • Prolonged prothrombin time (PT) 6
  • Early altered consciousness 6
  • Massive gastrointestinal bleeding 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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