Classical Childhood Infections and Their Rashes:

Classical childhood infections and their rashes

This section summarises seven classical childhood infections frequently tested in postgraduate exams and encountered in the emergency department: chickenpox (varicella), measles, mumps, rubella, erythema infectiosum (parvovirus B19), scarlet fever, and hand‑foot‑and‑mouth disease (HFMD). For each condition the pathogen, characteristic rash (morphology and distribution), important complications, targeted ED actions and public‑health priorities are presented with an emphasis on the distinguishing features that matter in the emergency context (UKHSA/RCEM guidance).

General approach to any febrile rash in children

• Prioritise ABCDE and resuscitate immediately if the child is unstable; any reduced conscious level, poor perfusion, respiratory compromise or airway threat requires urgent senior input.
• Rapidly exclude life‑threatening causes; a non‑blanching petechial or purpuric rash raises immediate concern for meningococcal sepsis - start the sepsis pathway and empirical antibiotics without delay.
• Triage and infection control are essential; suspected measles or varicella requires airborne‑precaution isolation (single room/negative pressure where possible) and prompt notification of infection control/public‑health (UKHSA).
• Use standard or droplet precautions for many other exanthems unless airborne spread is suspected.
• Take a focused history including vaccination status (MMR/MMRV), prodrome timing, contact/exposure (including pregnancy in household), immune status, lesion evolution (macule → papule → vesicle → crust), pruritus versus pain, and mucosal involvement.
• Perform a focused examination of lesion morphology and stage, distribution (face, trunk, palms/soles), enanthem (oral ulcers,...