The most common cause of an itchy throat is allergies, which occur as a result of an allergen triggering an immune response in the body, according to Healthline. Potential allergens include pollen grains from grass, weeds and trees; mold; animal dander; dust; and some foods, such as peanuts and strawberries.
Other potential reasons for an itchy throat include inhaling pollutants, such as chemicals, tobacco smoke or cleaning products, adds Healthline. An itchy throat is often the first sign of a sore throat, indicating a possible viral infection, such as a cold, flu or strep throat.
The length of time symptoms are present differentiates allergies from colds. An itchy throat that persists rather than progressing into a sore throat accompanied by other cold symptoms indicates an allergy, according to WebMD.