A.
1~3-year-old children are more common, infectious, but do not need isolation
B.
localized as a single, cluster or cluster of small blisters on oral mucosa such as gums, tongue、 lips, and buccal mucosa
C.
vesicles usually do not form ulcers after rupture, the surface is covered with yellow and white membrane-like exudates
D.
multiple small ulcers cannot be fused to irregular larger ulcers
E.
lymph nodes are not enlarged