<s>[INST] Hello, my husband has been experiencing for the first time in his life an allergic reaction or so we think this is an allergic reaction. It s primarily in his face and it s always random. It s been happening in the last couple of months and seems to happen only on the weekends, but again random, not all the time and it vasilates between the left side and the right side and usually his mouth area where he experiences swelling to the point of it hurting. We think either a food allergy or maybe spider bite, but we ve tried to narrow down the food items, laundry items, soaps, etc. and it s still happening. Could this be another way of his body telling him something else is wrong? When administering an allergy medicine to him, it will usually go away by the late afternoon or the next day and he always wakes up with it. Help! [/INST] HI, thanks for using Chat Doctor The symptoms are possibly due to : (1) allergies (2) sinus congestion (3) infection with herpes simplex 1 (cold sores)Sinus congestion can cause one-sided pain and swelling as could the other conditions mentioned. It would be best to consider visiting a doctor for an assessment which would include physical examination and possibly bloods. Blood tests can be done to check for allergies though if it is an allergy, it would have to be something coming into contact with this area specifically hope this helps </s>