Slapped cheek syndrome

(Fifth Disease, Erythema Infectiosum)

Definition
A mild, self-limiting viral infection most commonly affecting children, caused by parvovirus B19, characterized by a bright red rash on the cheeks followed by a lacy rash on the body.

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Cause

• Parvovirus B19 — spreads via respiratory droplets, blood transfusion, or vertically from mother to fetus

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Risk Groups

• Children aged 3–15 years

• Adults in contact with children (teachers, healthcare workers)

• Immunocompromised individuals

• Pregnant women (risk of fetal hydrops)

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Pathophysiology

• Virus infects and destroys erythroid progenitor cells in bone marrow

• Causes a brief drop in red cell production, which may trigger anaemia in susceptible patients (e.g., sickle cell disease)

• Immune-mediated skin rash appears after viraemia resolves

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Clinical Features

Stage 1 – Initial Phase (Viraemia)

• Low-grade fever

• Malaise, headache, mild cold-like symptoms

• Lasts 2–5 days; infectious at this stage

Stage 2 – Rash Phase

• Bright red “slapped cheek” facial rash

• Lacy, reticular maculopapular rash on trunk and limbs

• Rash may recur with heat, exercise, or sunlight

• Usually non-itchy in children; more pruritic in adults

Stage 3 – Arthropathy (especially in adults)

• Symmetrical joint pain and swelling (hands, wrists, knees, ankles)

• Lasts days to weeks

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Complications

• Aplastic crisis in haemolytic anaemias

• Fetal hydrops and miscarriage in pregnant women infected during early pregnancy

• Chronic anaemia in immunocompromised patients

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Diagnosis

• Clinical diagnosis based on typical rash pattern in children

• Confirm with Parvovirus B19 IgM antibodies in high-risk groups (pregnant women, immunosuppressed)

• PCR testing in immunocompromised or atypical cases

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Treatment

General

• No specific antiviral treatment; supportive care only

• Rest, adequate hydration

• Paracetamol 500–1000 mg every 4–6 hours (max 4 g/day) or ibuprofen 200–400 mg every 6–8 hours for fever and discomfort

Special Situations

• Immunocompromised or severe anaemia: consider hospital admission and intravenous immunoglobulin (IVIG)

• Pregnant women: monitor fetal wellbeing with ultrasound if infection confirmed

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Prevention

• Good hand hygiene

• No vaccine available

• Exclusion from school not required once rash appears (non-infectious phase)

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Quick-Reference Clinical Chart — Slapped Cheek Syndrome

Feature	Details
Definition	Viral childhood illness caused by parvovirus B19 with bright red cheek rash
Transmission	Respiratory droplets, blood, vertical (mother to fetus)
Incubation	4–14 days (up to 21)
Symptoms	Fever, malaise → “slapped cheek” rash → lacy body rash; joint pain in adults
Complications	Aplastic crisis, fetal hydrops, chronic anaemia
Treatment	Supportive: rest, fluids, paracetamol 500–1000 mg Q4–6h PRN or ibuprofen 200–400 mg Q6–8h PRN
Infectious period	Before rash onset; not infectious once rash appears
Prevention	Hand hygiene, no vaccine, exclude only if unwell
Prognosis	Full recovery in healthy individuals; severe risk in anaemia, pregnancy, immunosuppression