Itchy throat old cough with phlegm may be related to chronic pharyngitis, allergic pharyngitis, postnasal drip syndrome and other reasons. 1. Chronic pharyngitis: mainly manifested as pharyngeal foreign body sensation, itchy sensation, etc., there are often viscous secretions attached to the posterior wall of the pharynx, which can stimulate the pharynx to cause coughing with phlegm. 2. Allergic pharyngitis: due to allergen stimulation of the upper respiratory tract, can cause allergic reactions, when it occurs in the pharynx, there can be a tickling sensation and accompanied by coughing and phlegm symptoms. 3. Postnasal drip syndrome: Inflammation of the nasal cavity and sinuses causes excessive mucus secretion, which can flow back to the throat, leading to such symptoms. It is recommended that people who have itchy throat with cough and phlegm should go to the regular hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor, so as not to delay the disease to bring adverse effects on the body and increase the extra burden on the body.