Hand, foot, and mouth disease
Exam Tips
- Classic OSCE triad: mild fever + painful oral ulcers + acral papulovesicular rash (hands/feet, often dorsolateral digits).
- A6 clue: wider vesiculobullous eruption, perioral involvement, flexural/eczema-site accentuation, later peeling/nail shedding.
- Investigations are usually unnecessary in primary care; reserve PCR typing for severe/atypical, outbreak, pregnancy/neonatal, or EV71-risk travel contexts.
- Always assess hydration status and give explicit red-flag safety-netting; this is frequently examined.
- Do not prescribe antibiotics routinely; avoid aspirin in under-16s and use ibuprofen cautiously if dehydrated.
Definition
Hand, foot and mouth disease (HFMD) is an acute, usually self-limiting enteroviral infection (most often Coxsackie A16 or A6) that causes painful oral enanthem with a papulovesicular exanthem on distal limbs. It typically affects children under 10 years, has an incubation of about 3-5 days, and must be distinguished from animal foot-and-mouth disease, which is caused by a different virus.
Pathophysiology
After exposure (respiratory secretions, blister fluid, or faeco-oral spread), enteroviruses replicate in pharyngeal and intestinal lymphoid tissue, then disseminate via lymphatics/blood to skin and oral mucosa, producing vesicles that rapidly ulcerate in the mouth. Picornaviruses are non-enveloped single-stranded RNA viruses with environmental resilience, which helps transmission in childcare settings. Serotype influences phenotype: Coxsackie A6 is associated with more extensive vesiculobullous rash, higher fever, later desquamation/onychomadesis, and more adult infection; EV71 (rare in Europe) has greater neurotropism and risk of brainstem encephalitis/autonomic dysregulation.
Risk Factors
- Age under 10 years (especially under 4-5 years)
- Nursery/school attendance or household contact with infected child
- Poor hand hygiene, overcrowding, limited clean water access, large household size
- Immunocompromise or immunosuppressive therapy
- Recent travel to East or Southeast Asia (raises concern for EV71)
- Maternal peripartum infection (risk of neonatal transmission)
Clinical Features
Symptoms
- Prodrome (12-36 hours): low-grade fever (often 38-39 C), malaise, reduced appetite, sore throat/mouth
- Oral pain causing reduced intake or dehydration risk
- Myalgia, cough, abdominal pain; occasional vomiting (more reported with EV71)
- Rash discomfort or pain on hands/feet; sometimes asymptomatic skin lesions
- In atypical A6 disease: higher fever and more widespread rash, later skin peeling
Signs
- Oral lesions: 2-8 mm erythematous macules/papules progressing to vesicles then shallow yellow-grey ulcers with erythematous halo (hard palate, tongue, buccal mucosa, lips/pharynx)
- Skin lesions: 2-5 mm erythematous macules/papules with central grey vesicle, often elliptical and aligned with skin lines
- Distribution: sides/dorsum of fingers and hands, margins of heels/feet, sometimes buttocks/groin (especially infants)
- Atypical A6 pattern: more diffuse eruption including eczema-prone flexures, possible petechiae/purpura or larger bullae; prominent perioral cutaneous lesions
- Possible strawberry tongue in adults; erosive napkin dermatitis in young children
Investigations
Management
Lifestyle Modifications
- Encourage regular fluids and soft/cool foods; monitor urine output to prevent dehydration
- Hand hygiene, cleaning shared surfaces, and avoiding sharing cups/cutlery/towels
- Child can usually return to nursery/school when clinically well enough; prolonged exclusion is not required solely for rash because viral shedding may persist
- Give clear safety-net advice: urgent review for poor intake, drowsiness, persistent high fever, severe headache, neck/back stiffness, breathing difficulty, or reduced responsiveness
- See DermNet clinical image sets for pattern recognition of typical and atypical lesions
Pharmacological Treatment
Analgesic/antipyretic
- Paracetamol oral: child 3 months-11 years 15 mg/kg every 4-6 hours as needed (max 4 doses in 24 hours); age 12-17 years 500 mg-1 g every 4-6 hours (max 4 g/day)
First-line for fever and mouth pain; dose by weight in children; avoid unintentional overdose from combination products.
NSAID (if needed, second-line)
- Ibuprofen oral: child 3 months-11 years 5-10 mg/kg per dose 3-4 times daily (usual max 30 mg/kg/day); age 12-17 years 200-400 mg up to 3 times daily
Avoid/caution in dehydration, renal impairment, active GI ulceration, NSAID hypersensitivity/asthma sensitivity, and chickenpox due to risk of severe skin/soft tissue complications.
Complications
- Dehydration from painful oral lesions (most common)
- Secondary bacterial infection of skin lesions (uncommon)
- Post-infectious nail changes (Beau lines, leukonychia, discolouration, onychomadesis) weeks after illness
- Rare severe neurological/cardiopulmonary disease with EV71 (brainstem encephalitis, aseptic meningitis, acute flaccid paralysis, autonomic instability, pulmonary oedema, myocardial dysfunction)
- Pregnancy/perinatal concerns: possible neonatal infection if maternal infection occurs around delivery; severe neonatal systemic disease is rare
Prognosis
Overall prognosis is excellent: most children recover fully within 7-10 days without specific antiviral treatment. Recurrence can occur because immunity is serotype-specific (limited cross-protection between enteroviruses). A6 infections may be followed by temporary desquamation and nail shedding; severe long-term sequelae are uncommon and mainly linked to rare EV71-associated severe disease.
Sources & References
🏥BMJ Best Practice(1)
✅NICE Guidelines(1)
- Hand, foot, and mouth disease[overview]
📖Textbook References(2)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1496)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 156)[context]