Frequent fever

Patient: Doctor,my son has been getting fevers on and off for almost a year and a half now. its usually after every two weeks. each time he is given an antibiotic. we have lots of pet birds at home. our doctor asked us to get rid of all that. the doc said that he is also allergic to dust. his adenoid gland was affected followed by wheezing thrice. we have changed our residence. he still keeps getting the fever. since the past two months his fever comes down in two days, after a course of paracetamol. but it comes again after another week. he has taken a lot of antibiotics and the doctor said that he is resistant to most of them. pls advice me on what to do. he does not have an adenoid problem now. the fever is what is worrying me. i have noticed that a mild exposure to dust, smoke or even cold triggers a fever in him. he is on an antihistamine tablet everyday at night. pls help!