Allergic reactions create many breathing problems, from simple runny noses to life-threatening respiratory arrest. The immune system's abnormal response to harmless allergens unleashes histamines and other substances that work to restore equilibrium The side effects of this process result in respiratory and other allergy symptoms.
Complications can occur in people with extreme sensitivities to the allergenic proteins in some pollens, foods, household pollutants, animal secretions and other substances. Preexisting respiratory conditions also contribute to the severity of allergic effects on the respiratory system.
Allergic Rhinitis
Nasal and bronchial allergy symptoms can occur during allergic reactions to indoor and outdoor irritants. The University of Maryland Medical Center reports that breathing problems occur when histamines create inflammation in the nasal and sinus passages and lining of the throat.
Swelling intended to keep more allergens from entering the body restricts the airways. At the same time, fluids migrate to and clog the mucous membranes.
The resulting respiratory symptoms--including runny and stuffy nose, sinus congestion, postnasal drip, cough and sore throat--make breathing more difficult. Some sensitive patients experience extreme discomfort, especially from inhaled airborne allergens such as mold, pollen and dried pet dander.
Asthma
A condition called allergic asthma can add asthma symptoms to those of a regular allergic reaction. According to the American Academy of Allergy, Asthma and Immunology, people who have allergic asthma can develop these breathing problems when they encounter certain airborne, insect venom, food or drug allergens.
Inflammation of the bronchi and lungs reduce the space in the airways and affect oxygen transfer. This makes patients cough, wheeze and experience chest pain and shortness of breath. These allergy complications can be reversed with medication. Without intervention, asthma episodes can escalate until low blood oxygen levels can no longer sustain cellular metabolism. Respiratory arrest, organ failure and death may result.
Anaphylaxis
Rare allergic reactions produce another group of potentially fatal allergy symptoms, collectively called anaphylaxis. Most commonly caused by ingestion of allergenic medications or foods, anaphylaxis can also be brought on by a reaction to a bee, hornet, wasp or fire ant sting.
The Asthma and Allergy Foundation of America warns that anaphylaxis may arise suddenly, as soon as allergens enter a patient's bloodstream. As the airways constrict, the blood vessels widen, and blood pressure falls sharply. Breathing problems due to allergic and/or asthmatic inflammation interfere with oxygen transfer, creating a medical emergency similar to that induced by asthma. Patients should call 911 for paramedic help if they experience changes in pulse or dizziness along with respiratory allergy symptoms.
