These infections are known as a common cold, sinusitis (sinus infection), sore throat, and laryngitis. All of these infections can cause a cough that produces phlegm. Peter Ashman, M.D ...

When you have a viral infection, the mucus membranes in the back ... If your itchy throat is not accompanied by a cough, it may be due to strep throat, laryngitis, dehydration, or (rarely) throat ...