I have persistent itchy cough for a week now. i don't smoke and i just had a flu last week. i think its due to allergy, but how do i get rid of it?

Not uncommon: It is not uncommon to have a dry cough for several weeks after contracting flu. However this also raises the red flag that you may have a mild case of asthma which needs to be ruled out if the cough lasts > a month. Try honey in tea first but a cough suppressant may be considered if it is keeping you awake. If fever >102 or discolored sputum develops, need to rule out pneumonia.