6 year old cold/allergy induced asthma

My six year old has been diagnosed with cold/allergy induced asthma. This started when he was 2 months old. He caught a cold and them had coughing and wheezing. Was put on albuterol and predilisone. I have been fighting this battle since then. Whenever he gets a cold or congestion the asthma kicks in. He is currenlty on singulair and clarinex on a daily basis. when things get worse we add Qvar 2 puffs twice a day and xopenex 2 puffs every 4 hours when needed. If this doesn't work we add the predilisone 2 1/2 teaspoons for 5 days. I have tried everything - NAET treatments, accupunture, vitamins, peppermint tea, etc. I am concerned because i am not sure the singulair and clarinex are even working but i am afraid to take him off. The longest he ever went without medication was about 8 months. As soon as he catches a cold and his nose runs I start to get anxious. It's like a re-occuring nightmare. He just had a virus for 6 days with high fever. This did not worry me but I knew it was just a mater of days before the asthma would kick in. And it did 2 days after his fever his nose started to run and now the asthma is full blown. He coughed so much last night that his nose started to bleed. It kills me to see him like this. I would like to know if anyone has has any success with alternative treatments? thanks from a sleepless, anxious, desperate mom.