ok sinus problems are a whole new thing. but dont worry. there are things you can do. instead of spending your money on shaving your cat. try purchasing an air ionizer which can help remove pet dander from the air.
also u can purchase online a solution which you rub on your cat weekly. it helps reduce cat dander so that your allergies wont be so bad. its basically for cats with allergic owners. remove all furry things from your home-if possible. things like carpets and heavy curtains which collect dust and dander and can aggravate your symptoms. bathing your cat more often also helps allergy sufferers. some suggest once a week but if you dont want to dry out the skin perhaps twice a month is better. overly dry skin sheds more dander in fact so you should try to avoid getting into this situation as well. good luck..