Yes, allergies can cause phlegm. Phlegm is mucus produced by the respiratory system, in the lungs and throat. It is a thick secretion the body generates in response to irritation or inflammation. An allergy is an abnormal immune system reaction to substances harmless to most people, such as pollen or pet dander.
The Allergic Mechanism Behind Phlegm
When a person with allergies encounters an allergen, their immune system mistakenly identifies it as a threat. This triggers an immune response, releasing chemicals like histamine. Histamine causes inflammation in the mucous membranes of the nose, eyes, and throat. This inflammation increases mucus production as the body attempts to trap and remove the allergen.
Excess mucus often becomes thick and sticky, accumulating in the nasal passages and back of the throat. This buildup results in post-nasal drip, where mucus trickles down the throat. The irritation from this continuous dripping can lead to a cough, the body’s effort to clear these excess secretions, often bringing up phlegm.
Identifying Allergy-Related Phlegm
Distinguishing allergy-induced phlegm from phlegm caused by other conditions, like colds or infections, involves observing accompanying symptoms and phlegm characteristics. Allergy symptoms include sneezing, an itchy nose, throat, or eyes, and watery eyes. Nasal congestion and a runny nose are also signs of an allergic reaction. Unlike viral infections, allergies rarely cause fever, chills, or body aches.
Phlegm associated with allergies is clear or white. It can range from thin to slightly thick. In contrast, phlegm from a bacterial or viral infection often appears yellow or green, and tends to be thicker. If discolored and accompanied by symptoms like fever, it is more likely due to an infection than allergies.
Managing Allergy-Induced Phlegm
Managing allergy-induced phlegm involves strategies to reduce allergen exposure and alleviate symptoms. A primary approach is allergen avoidance, such as using dust-proof covers on bedding, washing linens in hot water, and keeping windows closed during high pollen seasons. For pet dander, limiting pets to certain home areas and frequent cleaning helps. Using high-efficiency particulate air (HEPA) filters in air conditioning systems or standalone units also reduces airborne allergens.
Over-the-counter medications provide relief. Antihistamines block histamine, reducing symptoms like sneezing, itching, and a runny nose. Nasal corticosteroids, often available as sprays, reduce inflammation and mucus production in the nasal passages. Decongestants alleviate a stuffy nose and pressure, though typically recommended for short-term use.
Simple home remedies complement other treatments. Drinking plenty of fluids thins mucus, making it easier to clear. Using a humidifier moistens the air, soothing irritated nasal passages and loosening mucus. Saline nasal rinses or sprays effectively clear mucus and allergens from the nose and sinuses. If symptoms persist for more than a few weeks, interfere with daily life, or are accompanied by difficulty breathing or chronic sinus infections, consult a doctor or allergist.