A viral exanthem is a widespread skin rash that comes with a viral infection, most often in children. Most are mild and self-limited, but the rash pattern helps identify measles, chickenpox and other infections that need isolation or public health action.
Key symptoms
- Fever, runny nose, cough or sore throat before or with the rash
- Red rash that spreads over the face, trunk or limbs
- Itchy blisters in chickenpox; mouth sores in hand, foot and mouth disease
- Tiredness, poor appetite and mild aches
What you find on exam
- Rash type and spread: maculopapular, vesicular or petechial
- Bright red cheeks in fifth disease; rash after fever falls in roseola
- Small white spots inside the cheeks in measles
- Check that the rash blanches; non-blanching spots need urgent action
- Hydration, lymph nodes, conjunctivae and general appearance
Tests
- Usually a clinical diagnosis
- Measles PCR or IgM if suspected, with report to public health
- Rapid strep test if scarlet fever is possible
- Blood count and cultures if the rash is petechial or the child looks ill
Treatment basics
- Supportive care: fluids, rest and acetaminophen for fever
- Isolation when contagious: airborne precautions for measles and chickenpox
- Vitamin A for children with measles
- Acyclovir for chickenpox in high-risk patients
- Check vaccination status and advise on exposure of pregnant contacts
Red flags
- Fever with a non-blanching petechial or purpuric rash
- Lethargy, stiff neck, dehydration or trouble breathing
- Exposure of a pregnant or immunocompromised person to measles, rubella, chickenpox or parvovirus
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.