About 20 % - 25 % of patients in disease before or at the same time is local have sao is urticant feeling , also have patients in stable condition of certain factors have itch , then the chital expand or appear new blaze .

有20%25%的患者在发病之前或同时局部有瘙痒感，亦有患者在病情稳定时因某种因素发生痒感，随之白斑扩大或出现新的白斑。