Can allergies cause postnasal drip?
Yes. Postnasal drip is one of the symptoms of allergic rhinitis, which is caused by allergens like molds, pollen and animals. The immune system overreacts by making IgE antibodies, which travel to cells that release histamine and other chemicals and cause symptoms such as sneezing, stuffiness, a runny nose, itching and postnasal drip.1
How allergies cause it
Postnasal drip is mucus that runs from the back of your nose down your throat.2 It is one of the symptoms of allergic rhinitis, along with sneezing, stuffiness, a runny nose and itching.1
Allergic rhinitis is caused by allergens like molds, pollen and animals.1 The immune system overreacts by producing antibodies called immunoglobulin E (IgE).1 These antibodies travel to cells that release histamine and other chemicals, which set off the allergic reaction and its symptoms.1
Seasonal allergic rhinitis is triggered by outdoor allergens such as pollen and mold spores.1 Some people have symptoms year-round because of indoor allergens from pets, mold, dust mites and cockroach residue.1 Throughout the US, trees produce the most pollen from February through April, grass pollen is most common from April through early June, and weed pollen appears in the late summer and fall.2
Postnasal drip and coughing
When you have rhinitis, your nose may produce more mucus.6 When more mucus drains down the back of your throat, substances in the mucus may irritate it and cause coughing.6 Postnasal drainage is one of the most common causes of chronic cough, a cough present for eight weeks or more, along with asthma and gastroesophageal reflux disease (GERD).7
Allergies or something else?
Mucus dripping down the throat is also a symptom of a sinus infection.8 The other signs are a runny nose, a stuffy nose, facial pain or pressure, headache, sore throat, cough and bad breath.8 A previous cold and seasonal allergies are among the risk factors for a sinus infection.8 Viruses cause most sinus infections, but bacteria can cause some.8
AAAAI lists thick, discolored nasal drainage and a bad-tasting postnasal drip among the symptoms of sinusitis.9
When to see a doctor
For a possible sinus infection, CDC advises seeing a healthcare provider for severe symptoms, such as severe headache or facial pain; symptoms that get worse after improving; symptoms lasting more than 10 days without getting better; a fever longer than 3 to 4 days; or multiple sinus infections in the past year.8
AAAAI suggests seeing an allergist if you have a cough that lasts more than eight weeks, if your cough is associated with symptoms of asthma, nasal symptoms or tobacco use, or if it is severe and affecting your quality of life.7 An allergist can help diagnose the cause of a chronic cough.7
Related conditions
Cold or allergies?
Compare your symptoms with a cold and with allergies in a few questions. Your answers stay in your browser.
When to get help
See an allergist if
- Allergy symptoms last for several months of the year
- Allergies bring repeated sinus problems, a blocked nose or trouble breathing
- Over-the-counter remedies don’t control your symptoms
- Allergies or asthma get in the way of daily life
- You often wheeze, cough at night or after exercise, or feel short of breath
Based on ACAAI’s “When To See an Allergist”. General information, not medical advice.
Questions
Can postnasal drip from allergies cause a cough?
Yes. When more mucus drains down the back of your throat, substances in the mucus may irritate it and cause coughing.6
Is a cough that won’t go away linked to postnasal drip?
It can be. A cough is usually described as chronic if it is present for eight weeks or more, and the most common causes of chronic cough are postnasal drainage, asthma and gastroesophageal reflux disease (GERD).7
Sources
- Rhinitis (Hay Fever). American Academy of Allergy, Asthma & Immunology. Read on October 16, 2026.
- Pollen Allergies. Asthma and Allergy Foundation of America. Read on October 16, 2026.
- Mold Allergy. Asthma and Allergy Foundation of America. Read on October 16, 2026.
- Allergic to Your Pet? Learn About Dog and Cat Allergies. Asthma and Allergy Foundation of America. Read on October 16, 2026.
- Hay Fever. American College of Allergy, Asthma and Immunology. Read on October 16, 2026.
- Nasal Allergies (Rhinitis). Asthma and Allergy Foundation of America. Read on October 16, 2026.
- Chronic Cough. American Academy of Allergy, Asthma & Immunology. Read on October 16, 2026.
- Sinus Infection Basics. Centers for Disease Control and Prevention. Read on October 16, 2026.
- Sinusitis. American Academy of Allergy, Asthma & Immunology. Read on October 16, 2026.