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. Children younger than 5 years are predominately more symptomatic than older patients. The exanthem involves the palmar, plantar, and interdigital surfaces of the hands and feet. These lesions may be asymptomatic or pruritic.