The most commonly implicated enterovirus is coxsackievirus A16. However, coxsackieviruses A5, A9, A10, A16, B1, and B3, as well as herpes simplex viruses, can cause the illness. Respiratory droplet transmission also may occur but is less likely. Complications are rare, but as with any pruritic rash, a secondary skin infection may occur. Males and females are affected with equal frequency.
Males are more likely to become symptomatically ill.
The usual incubation period is 3-6 days. The prodrome precedes the development of oral lesions, followed shortly by skin lesions, primarily on the hands and feet and occasionally on the buttocks. Yellow ulcers surrounded by red halos characterize the oral lesions. These occur primarily on the labial and buccal mucosal surfaces, but they may be observed on the tongue, palate, uvula, anterior tonsillar pillars, or gums. The oral ulcers are usually only mildly painful.