hi my 13 year old son have frequent low grade (morning 98.-evening 99.3) fever from last 5 years,he have persistent cough and running nose .he tested positive moltulx test 14*14, blood count and chest x ray is normal, some time he feels tired , althought his doctor not adviced to start any tuberculosis drug . what may be the cause? ,he use to take anti allergic drug but nothing help .his height is also not increasing from last 2 years, and lost 2 kg body weight (from 47 to 45)