What Causes Nasal Congestion Allergies?

Nasal congestion, a hallmark of airborne allergies, can be a petty annoyance. But if the nasal passages become infected, symptoms are increasingly worse. Nasal congestion often indicates that something in the air is causing your problems--either outdoors or in your indoor environment. Understanding the reason for your nasal congestion entails knowing what causes your allergies, right down to identifying the particles that cause this response.

What Causes Allergies?

• Allergies are the result of a faulty immune system that mistakenly identifies certain proteins found in innocuous substances as harmful invaders. In response to exposure to these proteins, the body's immune system produces its own proteins, called IgE antibodies. Under normal circumstances, these antibodies protect you from harmful substances that cause infection and illness. However, if you have allergies, the immune system dispatches the antibodies to otherwise harmless substances, triggering the release of histamines that cause a host of unpleasant symptoms, including nasal congestion.

Why Do Allergies Cause Nasal Congestion?

• The nasal airway and tissues in the sinuses, being the airborne allergen's first point of contact, are also one of the first to respond. The nose and sinuses become irritated and inflamed as the antibodies do battle with the allergen, causing congestion and other symptoms. Nasal congestion is also known as "allergic rhinitis" in medical terminology. Another common name for nasal congestion that results from allergies is "hay fever," thus named because of symptoms that developed during hay season. If you suffer from nasal congestion, you may feel other effects of hay fever as well, including itchy, watery eyes and blocked ears.

When Does Nasal Congestion Occur?

• If the allergy is the result of pollen, nasal congestion will frequently occur during the spring, summer and fall, when trees, grasses and weeds, respectively, are producing the most pollen. One of the worst allergens is ragweed, which blooms from late summer until frost. But you can also be allergic to substances in your household environment. Other common airborne allergens are dust mites, mold spores, animal dander, feathers and certain chemical pollutants. While nasal congestion is typically associated with exposure to airborne particles, you can also suffer from nasal congestion if you're allergic to specific foods, insect venoms and certain drugs.

Identifying the Source of Nasal Congestion

• To determine if nasal congestion is the result of an allergy, a doctor may recommend certain testing procedures. During a skin test, the skin is pricked and exposed to the proteins found in specific allergens. A positive reaction on the skin--a raised red welt--indicates an allergic response. Blood testing also identifies sensitivity to allergens by measuring the amount of IgE antibodies in the bloodstream. Both tests aid in narrowing the list of culprits that may cause your nasal congestion. A detailed diary of when you've experienced past nasal congestion, as well as the type and severity of your symptoms, is also helpful to your doctor.

Treating Allergy-Related Nasal Congestion

• The most efficient way to reduce nasal congestion related to allergies is to avoid the substances that cause this response. Keeping your household free of dust, molds and other environmental allergens can greatly reduce nasal congestion. However, this might not be entirely possible when the allergens are pollens. Medication is used to reduce the immune system's response and assuage symptoms. Drugs used can be over-the-counter or prescribed by your doctor, and can come in the form of oral medication, nasal sprays and eye drops. If your nasal congestion is severe and pervasive, you may consider immunotherapy, in which allergy injections are given over a series of years to desensitize you from certain allergens.

Be Prepared for Nasal Congestion Allergies

• If your allergies are cause by airborne pollens, it's often helpful to know when you might experience nasal congestion. The American Academy of Otolaryngic Allergy has provided a seasonal chart in the link below that can tell you when ragweed and tree and grass pollens are in bloom (click on "pollen map" under Patient Resources).