Just getting in my office. Although the individual lesion

doesn't show up clearly in the pciture, I still can see the distribution of the lesions, and roughly the characteristics of them. They are not 病毒感染引起的. 小鸟's diagnosis is very likely although you said it's not itching (痒), but you really can't tell from a three year old. The fact that he/she scratched it (孩子开始抓手) means it's most probably itching.