For regular mucus formation and cold.

Hello Doctor, I am a professional singer and i keep performing regularly at various events and concerts. My general query is about frequent mucus formation and cold. I had mild Sinus problem. On normal days, mucus keeps on gathering in my throat and then I have to clear it frequently everytime I start to sing or talk. Also, Whenever I get exposed to weather change, i m bound to get cold and then the cold lasts a month, followed by dry cough leading to voice loss which takes another month to recover. Lately, i faced swelling in my throat which took me 2 months to recover from after taking heavy steroids. Now, that I was back on track and was pursuing my regular practice, again this allergic cold has caught me and now I am afraid of the cough and voice loss all over again. Please suggest something to improve my immunity against these regular cold coughs and how too cope with these colds quickly so that my voice doesn't suffer much. Your help is urgently needed. Regards Manya Narang