Fifth disease is a common childhood infection with parvovirus B19 that causes bright red cheeks and a lacy body rash. It is mild in most children, but the virus can stop red cell production, which is dangerous in sickle cell disease, in weak immunity and for the unborn baby.
Key symptoms
- Low fever, runny nose and headache a week before the rash
- Bright red cheeks, like a slap
- Lacy rash on arms, legs and trunk that comes and goes with heat
- Joint pain and swelling in hands, wrists and knees, mostly in adults
- Fatigue and pallor in people with chronic anemia
What you find on exam
- Red cheeks with paleness around the mouth
- Reticular, lace-like rash on the limbs
- Symmetric swelling of small joints
- Pallor and fast heart rate if anemia is severe
- Ask about pregnancy, sickle cell disease and immune problems
Tests
- Usually a clinical diagnosis in children
- Parvovirus B19 IgM and IgG in pregnancy or in adults with arthritis
- Blood count and reticulocyte count in anemia or weak immunity
- Exposed pregnancy: serial fetal ultrasound and middle cerebral artery Doppler
Treatment basics
- Rest, fluids and acetaminophen for fever
- NSAIDs such as ibuprofen for joint pain
- Children can attend school once the rash appears; they are no longer contagious
- Transfusion for aplastic crisis; IVIG for chronic infection in weak immunity
- Intrauterine transfusion if the fetus becomes severely anemic
Red flags
- Pallor, fatigue and fast heart rate in sickle cell disease
- Exposure or infection during pregnancy
- Persistent anemia in a weakened immune system
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations. Written by Making Synapses. Making Synapses is not affiliated with these organizations.