Son is suffering allergy every night. It's like when we he is off to bed he asks to itch his back and then it turns red with raised skin of different shapes..it's happening at night and then by morning he is all fine.. it's been happening for a week now.. we r not even able to understand why is the allergy happening because he has not even been introduced to new food or habit. Sometimes the allergy can be seen behind ears also but weird thing is it happens at night only when he is off to bed.. we try changing clothes.. apply aloe vera gel .. soothing cream .. wiping his body.. but still it appears.. why?