A 6-year-old child from Delhi presents with fever, myalgia, and rash on day 5 of illness. Investigations show thrombocytopenia and elevated transaminases. What is the most common hemorrhagic manifestation in dengue fever in children?

Explanation

## Most Common Hemorrhagic Manifestation in Pediatric Dengue ### Petechial Rash as the Primary Hemorrhagic Sign **Key Point:** Petechial rash is the most common hemorrhagic manifestation in dengue fever in children, occurring in 40–50% of cases with hemorrhagic features. It typically appears on the lower extremities, trunk, and pressure areas during the critical phase (days 3–7 of illness). ### Pathophysiology 1. Dengue virus infects endothelial cells and causes vasculitis 2. Thrombocytopenia develops (platelet count often <100,000/mm³) 3. Increased vascular permeability leads to plasma leakage 4. Combination of thrombocytopenia + endothelial damage → petechiae ### Clinical Presentation Spectrum | Hemorrhagic Manifestation | Frequency in Children | Severity | |---|---|---| | Petechial rash | 40–50% | Mild–moderate | | Gum bleeding | 15–25% | Mild | | Hematemesis | 5–10% | Moderate–severe | | Intracranial hemorrhage | <1% | Severe/fatal | | Pulmonary hemorrhage | <1% | Severe/fatal | **High-Yield:** The **petechial rash is a cardinal sign** of dengue hemorrhagic fever (DHF) and is part of the WHO case definition. Its presence helps distinguish DHF from dengue fever without hemorrhage. ### Clinical Pearl A **positive tourniquet test** (petechiae appearing after inflating a blood pressure cuff for 5 minutes) is a bedside marker of increased capillary fragility and predicts hemorrhagic manifestations. This is highly specific for dengue in endemic areas. ### Why Petechiae Are Most Common - Occur early in the hemorrhagic phase (day 3–5) - Result from mild endothelial damage + mild-to-moderate thrombocytopenia - Do not require severe coagulopathy or massive platelet depletion - Visible on skin examination, making them clinically apparent **Warning:** Severe hemorrhagic manifestations (hematemesis, intracranial bleed, pulmonary hemorrhage) occur only in dengue shock syndrome or with platelet counts <20,000/mm³ and are much rarer in children than in adults. [cite:Park 26e Ch 12]