Patients were prospectively enrolled in a tertiary medical center in Taipei, Taiwan. The definition of atypical
HFMD includes symptoms of acute viral infection with either of the following presentations: (1) maculopapular rashes
presenting on the trunks, buttocks or facial areas, or (2) large vesicles or bullae on any sites of the body. Patients were
classified into two groups according to vesicle sizes by two pediatricians at different points in time. The large vesicle
group was defined as having vesciculobullous lesions ≥ 1 cm in diameter; the small rashes group had maculopapular
rashes < 1cm in diameter. Two throat swabs were collected from each patient for virus isolation and reverse
transcription polymerase chain reactions.