For the past two weeks , my right hand is itching , only the area which I have shown in the picture I feel itching for 4-5 times per day. Once I scratch my hand with my left fingers, it becomes reddish and mosquito bite like bubble appears on the scratched area. After 10-15 mins it becomes normal. I don't feel this itching in any other part, it's only happening in my right hand in the area shown in the picture.