The American Academy of Allergy, Asthma and Immunology, or the AAAAI, says the most common cause of a chronic cough is allergic rhinitis, or hay fever. Hay fever is a chronic allergic condition that affects the sinuses, throat and eyes, according to MayoClinic.com. FamilyDoctor.org says a chronic cough is any cough that lasts for more than three weeks. Coughing is a defense mechanism the body uses to prevent allergens from entering the lungs and is typically initiated by postnasal drip. FamilyDoctor.org recommends seeing a doctor if someone develops a chronic cough for proper diagnosis.
Postnasal Drip
Postnasal drip is the result of excess mucus in the sinus cavity that drains in the back of the throat, according to the American Academy of Otolaryngology. Postnasal drip can cause bad breath, a sour stomach and throat irritation, leading to a sore throat. As mucus drips in the back of the throat, it can build up, causing excessive mucus. The body responds by coughing, attempting to break up the mucus and discard it by swallowing it. Postnasal drip from allergies is commonly treated with antihistamines to prevent histamine from being released in the bloodstream.
Allergy-Induced Asthma
According to MayoClinic.com, allergy-induced asthma can result in chronic coughing. When the immune system reacts to an allergen, it produces histamines that can trigger the lungs to become inflamed and tighten. This reaction can cause asthmatic reactions such as wheezing, difficulty breathing and coughing. This condition should be under a doctor's supervision to provide an asthma attack plan and the most effective treatment. Even people who don't have asthma can suffer from asthma-like symptoms from allergies. Allergy-induced asthma is treated by avoiding allergens and prescribed medications.
Other Symptoms
Other allergy symptoms can include nasal discharge, sneezing, congestion and irritation in the eyes and throat, according to MayoClinic.com. Someone with allergies may experience sinus headaches due to inflammation in the sinuses that press on various parts of the head such as the eyes, cheekbones and inner ear. Sinus pressure pain is treated with over-the-counter pain relievers and decongestants. Eye irritation results in watery eyes that may appear to be pink or red and itchy. The back of the throat can become itchy and irritated as a result of an allergic reaction.
