A constant tickle in the throat is a common symptom of post-nasal drip due to allergic rhinitis, an upper-respiratory condition triggered by allergens, according to WebMD. Additional symptoms of allergic rhinitis can include nasal congestion, chronic coughing, facial pain, and itching, watery eyes.
Allergens that can cause allergic rhinitis include outdoor pollens, cigarette smoke, dust mites and pet dander, according to the American Academy of Asthma and Immunology. Corticosteroid nasal sprays, antihistamine medications and decongestants can treat allergic rhinitis. Individuals with chronic rhinitis may also benefit from immunotherapy allergy shots. Patients can also manage nasal congestion with saline solutions and nasal decongestant sprays.