One of the roles of the immune system is to destroy harmful substances in the body. If a person has an allergy to a substance, their immune system will react as though that substance is harmful and will try to destroy it. Over 50 million people in the United States experience an allergic reaction each year. This reaction can lead to symptoms such as swelling.
If swelling affects the airways, it can become life threatening. In this article, learn about the risk factors, symptoms, and treatments associated with allergies. The first time a person is exposed to an allergen, they do not usually experience a reaction.
It often takes time for the immune system to build up a sensitivity to the substance. In time, the immune system learns to recognize and remember the allergen. As it does so, it starts making antibodies to attack it when exposure occurs.
This buildup is called sensitization. Some allergies are seasonal. For example, hay fever symptoms can peak between April and May, when the tree and grass pollen count in the air is higher. A person may experience a more severe reaction as the pollen count rises. Is it an allergy or an intolerance? Learn about the differences here. An allergic reaction causes inflammation and irritation.
However, the specific symptoms will depend on the type of allergen. For example, allergic reactions may occur in the gut, skin, sinuses, airways, eyes, or nasal passages. Anaphylaxis is the severest form of allergic reaction. It is a medical emergency and can be life threatening. Anaphylaxis can develop quickly, with symptoms appearing within minutes or hours of exposure to the allergen.
Research suggests that anaphylaxis most commonly affects the skin and respiratory system. Learn more about the symptoms of anaphylactic shock here. When an allergic reaction occurs, allergens bind to antibodies that the body produces called immunoglobin E IgE. Antibodies combat foreign and potentially harmful substances in the body.
Once the allergen binds to IgE, specific types of cells — including mast cells — will release chemicals that trigger the symptoms of the allergic reaction.
Histamine is one of these chemicals. It causes the muscles in the airways and walls of the blood vessels to tighten. It also instructs the lining of the nose to produce more mucus. People may have a higher risk of allergies if they are under 18 years old or have a personal or family history of asthma or allergies. Accessed July 28, Allergic reactions.
American Academy of Allergy, Asthma and Immunology. Seidman MD, et al. Clinical practice guideline: Allergic rhinitis. Otolaryngology — Head and Neck Surgery. Allergies and hay fever. Types of allergies. Who has allergies? What causes asthma? American Lung Association. Is rinsing your sinuses with neti pots safe? Food and Drug Administration. Related Allergy medications: Know your options Allergy-proof your home Does honey offer sweet relief for allergies?
Nasal Cleaning Nasal spray addiction: Is it real? Show more related content. Associated Procedures Allergy skin tests. News from Mayo Clinic Allergy or irritant? During an allergic reaction, these areas can become swollen, inflamed or itchy, with extra mucus produced in the nose and fluid in the eyes.
The lungs are also affected by allergens that are inhaled. Some people with asthma find their condition is triggered by allergens; however, it is possible to have asthma that is not caused by allergens, too.
The stomach and bowel are affected by allergens that are in foods or liquids that we ingest. Symptoms of an allergic reaction triggered by food or drink can include abdominal upsets like nausea, vomiting, or abdominal pain. Eczema and asthma can also be triggered by ingested allergens. Hives on the skin can be caused by allergens that have been ingested or allergens that have come into contact with the skin. Some people identify allergies early in life, while others develop allergies as they age.
Some people are genetically predisposed to developing allergies. People with atopy, or atopic people, may have eczema, hay fever or asthma. Some have all three of these conditions. The Australasian Society of Clinical Immunology and Allergy has a guide for parents introducing food to their babies. The severity of an allergic reaction can vary from mild to severe, changing from person to person and in one person from each exposure to an allergen.
Some allergic reactions, like watery eyes from hay fever, cause irritation or discomfort, but are not severe. Other allergic reactions, like anaphylaxis, can be immediately life-threatening, and should be taken extremely seriously.
0コメント