Hand, foot, and mouth disease: Red flags pediatricians should know

Hand, foot, and mouth disease (HFMD) remains a common pediatric infection, particularly among children younger than 5 years, but clinicians should recognize that some patients may develop severe complications beyond the characteristic fever, rash, and painful oral lesions, according to Hai D. Nguyen-Tran, MD.

Nguyen-Tran, an assistant professor at the University of Colorado and pediatric infectious diseases specialist at Children's Hospital Colorado, discussed the clinical presentation, potential complications, supportive management, and prevention of HFMD at the American Academy of Pediatrics (AAP) 2026 National Conference & Exhibition.

Although most children recover within approximately 1 week, Nguyen-Tran emphasized the importance of identifying dehydration and recognizing uncommon but potentially life-threatening neurologic complications.

What are the typical clinical signs of HFMD?

HFMD most frequently affects children younger than 10 years, particularly those younger than 5 years. The classic presentation includes fever, sore throat, and a papulovesicular rash involving the hands, wrists, feet, ankles, and mouth.

Lesions may also develop near the buttocks or genital region. Painful oral lesions can make eating and drinking difficult, increasing the risk of dehydration.

Nguyen-Tran noted that pediatricians may encounter less typical presentations, including eczema coxsackium, in which the eruption takes on a more widespread, eczema-like appearance.

While the clinical presentation generally remains consistent with historical patterns, clinicians should remain attentive to symptoms that extend beyond uncomplicated HFMD.

Which symptoms suggest serious complications?

Although severe complications are uncommon in the United States, Nguyen-Tran emphasized that neurologic involvement can occur, including brainstem encephalitis.

Children who initially present with typical HFMD symptoms may subsequently develop ataxia, lethargy, difficulty walking, or respiratory problems. In severe cases, neurologic involvement can progress to autonomic instability and cardiopulmonary failure.

Nguyen-Tran noted that outbreaks involving serious neurologic complications have occurred in the Asia-Pacific region, where outbreaks may recur every 3 to 4 years. She also referenced a significant 2018 outbreak in Colorado.

Pediatricians should counsel families to monitor for prolonged fever lasting several days, vomiting, marked lethargy, difficulty walking, or difficulty breathing.

"The warning signs that pediatricians should really think about and look out for are things like prolonged fevers for several days, kids that are vomiting-they're really lethargic. They have trouble walking and trouble breathing," Nguyen-Tran said.

Children developing these symptoms should receive prompt medical evaluation, particularly when neurologic changes or breathing difficulties are present.

How should pediatricians manage uncomplicated HFMD?

Most cases of HFMD are self-limited and resolve within approximately 1 week. However, painful oral lesions can substantially affect oral intake and create challenges for children and caregivers.

Nguyen-Tran emphasized supportive management, including appropriate pain relief and maintaining hydration.

Ibuprofen or acetaminophen may help reduce discomfort, allowing children to eat and drink more comfortably.

"The most important thing is hydration, hydration, hydration," Nguyen-Tran said.

In addition to water, electrolyte-containing beverages may help maintain fluid intake. Soft foods, such as yogurt or mashed potatoes, may be better tolerated when oral lesions are painful.

Cold foods, including popsicles, may provide both hydration and temporary relief from oral discomfort.

Pediatricians should encourage caregivers to monitor fluid intake and signs of dehydration throughout the illness, particularly when children are reluctant to drink.

How can families prevent transmission and determine when children can return to school?

HFMD is caused by enteroviruses, which can spread readily among children, particularly in school and child care settings.

Although most children improve within a week and are generally less contagious as symptoms resolve, Nguyen-Tran explained that viral shedding may continue in respiratory secretions and stool for weeks after the initial illness.

Consequently, infection prevention remains important even after children appear clinically recovered.

"The most important thing to prevent the spread of this infection is good hand washing," Nguyen-Tran said.

She recommended reinforcing hand hygiene, discouraging children from touching their faces or mouths with unwashed hands, and limiting behaviors such as nail biting or thumb sucking.

Return-to-school decisions should follow applicable local public health guidance and individual school or child care policies.

In general, Nguyen-Tran explained that children may return when they are feeling better, are afebrile, and are not experiencing excessive drooling.

However, she cautioned that requirements may differ by institution and jurisdiction.

For pediatricians, Nguyen-Tran's recommendations underscore the importance of balancing reassurance about the typically mild course of HFMD with clear guidance about hydration, warning signs of complications, and infection prevention.

Reference

Nguyen-Tran H. Hand, Foot, Mouth and What Disease?!. Presented at: American Academy of Pediatrics 2026 National Conference & Exhibition; October 5, 2026; San Diego, CA.