Hand-Foot-Mouth Disease

A 3-year-old at daycare won't eat or drink and is drooling — the blisters in the mouth explain the refusal, and the ones on the palms and soles tell you exactly what this is.

Hand-foot-mouth disease (HFMD) is caused primarily by Coxsackievirus A16 and less commonly by Enterovirus 71 (which carries higher risk for neurologic complications). It is most common in children under 5 years and is a frequent cause of daycare and preschool outbreaks. Transmission: fecal-oral route, respiratory droplets, and direct contact with vesicular fluid. The virus can be shed in stool for weeks after clinical recovery. Clinical presentation follows a typical pattern: low-grade fever and malaise for 1–2 days, then painful oral ulcers (tongue, buccal mucosa, hard palate), followed by a vesicular rash on the palms of the hands, soles of the feet, and often the buttocks. Perioral lesions can occur, especially with atypical strains such as Coxsackievirus A6, so distribution plus palms/soles/buttocks and outbreak context is more reliable for diagnosis than any single anatomical exclusion. The rash is usually not pruritic. The disease is self-limiting, resolving in 7–10 days. Treatment is entirely supportive: acetaminophen or ibuprofen for pain and fever, cool fluids and soft bland foods (popsicles, yogurt, cold milk — avoid acidic foods and beverages which increase oral pain), and monitoring for dehydration from poor oral intake due to mouth pain. There is no antiviral treatment and no vaccine is routinely available in the US. Complications are rare but include viral meningitis, encephalitis, and myocarditis — more commonly associated with Enterovirus 71 than Coxsackievirus A16. Nail shedding (onychomadesis) may occur weeks after resolution and is benign. Standard and contact precautions. Return to school or daycare when fever-free, feeling well enough to participate, and oral lesions are no longer causing uncontrolled drooling. Nursing: the primary concern is dehydration — assess oral intake, urine output, mucous membranes, and fontanelle in infants. Good hand hygiene especially after diaper changes is the key prevention measure. Disinfect toys and surfaces. Educate parents that the illness is self-limiting and complications are very rare.

Key Distinctions

The pathognomonic pattern is palms, soles, and buttocks PLUS oral ulcers — this combination differentiates HFMD from herpangina (posterior pharynx ulcers only, without extremity rash), varicella (central trunk distribution spreading outward, vesicles on erythematous base in different stages), and herpes simplex (typically lips and perioral area). HFMD oral lesions are primarily INSIDE the mouth (tongue, buccal mucosa, palate), while herpes simplex typically involves the LIPS and perioral skin, though atypical HFMD strains can cause perioral involvement. Students sometimes confuse the rashes — the combination of palms/soles/buttocks is the key differentiator.

Clinical Pearl

Palms, soles, buttocks, and mouth blisters — that's the HFMD fingerprint. Trunk-first is varicella, lips are herpes, posterior throat only is herpangina.