Severe nasal congestion and/or nasal polyps might, in part or whole, be caused by an allergy to cows milk. To test, completely eliminate cows milk for 12 weeks including prepared foods that contain milk, casein, lactalbumin, whey, or powdered milk. Its important to cut cows milk completely. You can use soya milk as a substitute. Inalation of a saline solution should help the healing process. Mix one quarter of a teaspoon of salt into a mug and inhale into one nostril while closing the other. Repeat. Also decreasing intake of omega-6 (fatty acids found in processed foods, margarine, polyunsaturated vegetable oils) and increasing intake of omega-3 fatty acids (oily fish, walnuts, fish oil supplements) will help long term. Also take daily garlic (or garlic supplement) as this safe but potent antifungal agent will combat sinus infections particularly if patient has been taking decongestants or steroids.