Adult Exposure to Hand-Foot-Mouth Disease: Clinical Course and Outcome

Case at a Glance

A 34-year-old healthy male presented with mild upper respiratory symptoms following close contact with his 1-year-old nephew who had been diagnosed with hand-foot-mouth disease (HFM). The patient was concerned about developing the characteristic vesicular rash and had self-medicated with valacyclovir.

Patient's Story

The patient reported exposure to his 1-year-old nephew who had developed a mild case of hand-foot-mouth disease starting July 9th. The nephew's illness began with a one-day fever followed by a localized rash on the foot that appeared to be healing rapidly. The patient had close contact with the child from July 13-15. On July 14th, he developed a mild sore throat and rhinorrhea. By July 15th, the sore throat had improved but nasal congestion persisted. Concerned about developing HFM, he self-administered valacyclovir 1000mg twice daily and increased his multivitamin intake. He remained afebrile and had no visible skin lesions at the time of presentation.

Initial Assessment

The patient appeared well with mild upper respiratory symptoms. No fever was documented, and physical examination revealed no vesicular lesions on hands, feet, or oral cavity. The patient reported no difficulty swallowing or eating. He was otherwise healthy with no significant medical history or immunocompromising conditions.

The Diagnostic Journey

Given the recent exposure history and mild symptoms, the differential diagnosis included hand-foot-mouth disease, common viral upper respiratory infection, or early viral prodrome. The patient's symptoms were consistent with either condition, as HFM can present with nonspecific prodromal symptoms before the characteristic rash appears.

Final Diagnosis

Probable viral upper respiratory infection with possible early hand-foot-mouth disease exposure. The patient was counseled that definitive diagnosis would depend on clinical course over the following days.

Treatment Plan

Discontinuation of unnecessary valacyclovir was recommended, as this antiviral is not indicated for hand-foot-mouth disease (caused by enteroviruses, not herpes viruses). Supportive care with rest, hydration, and symptom monitoring was advised. The patient was educated that antivirals are not effective against enteroviruses and that HFM typically follows a self-limiting course in healthy adults.

Outcome and Follow-up

The patient was advised to monitor for development of characteristic vesicular lesions on hands, feet, or in the oral cavity over the next 3-7 days. He was reassured that many adults exposed to HFM do not develop symptoms or may have very mild illness. Follow-up was recommended if symptoms worsened or if characteristic rash developed. The patient was counseled on appropriate hygiene measures to prevent further transmission.