PE31.10 | Exanthematous Illnesses — Summary & Reflection

KEY TAKEAWAYS

Exanthematous illnesses at a glance:

• Measles (paramyxovirus): 3 C's prodrome → Koplik spots (pathognomonic) → cephalocaudal maculopapular rash; manage with vitamin A (200,000/100,000/50,000 IU by age); serious complications: pneumonia, encephalitis, SSPE (7–10 years later), corneal blindness

• Rubella (togavirus): mild, self-limiting in children; post-auricular lymphadenopathy; rapidly fading rash; danger = Congenital Rubella Syndrome (deafness, PDA, cataracts) if infects first-trimester pregnant woman

• Chickenpox (VZV): polymorphic crops at different stages simultaneously; intensely pruritic; acyclovir for immunocompromised and severe cases; aspirin absolutely contraindicated (Reye syndrome); VZV establishes latency → herpes zoster in later life

• Roseola (HHV-6): high fever in infants → fever resolves → rash appears on trunk

• Erythema infectiosum (parvovirus B19): 'slapped-cheek'; lacy reticular rash; risk = aplastic crisis in haemolytic anaemias, fetal hydrops in pregnant contacts

• HFMD (coxsackievirus A16): oral ulcers + vesicles on palms/soles; supportive management

• Scarlet fever (Group A Strep): sandpaper rash, strawberry tongue, Pastia lines; treat with penicillin 10 days to prevent rheumatic fever

• Prevention: MMR at 9–12 months + booster 16–24 months; varicella vaccine at 15 months + 4–6 years

REFLECT

Consider your last clinical exposure to a febrile child with a rash: How confident were you in the diagnosis? What feature would have changed your differential? Now that you have completed this module, identify one exanthem whose diagnosis you previously found challenging and the specific clinical sign that will anchor your recognition going forward. Reflect on why vitamin A supplementation in measles — a nutritional intervention — can prevent blindness and death: what does this tell you about the intersection of nutritional status and infectious disease outcomes in paediatric practice?