Allergies can best be described as: An overreaction from the immune system to a foreign substance Allergies are an overreaction from the body’s immune system to foreign substances called allergens. Allergic reactions can result in sneezing, coughing, runny nose, and itching. Most of the time the reactions are bothersome, but in some cases they can be life-threatening and severe. Allergies may be seasonal, such as hay fever, but they may also be associated with chronic conditions such as asthma or sinusitis. Anaphylaxis is a basic reaction to a simple allergen. Anaphylaxis (anna-fill-ax-iss) is often triggered by substances that are injected or ingested and thereby gain access into the blood stream. An explosive reaction involving the skin, lungs, nose, throat, and gastrointestinal tract can then result. Although severe cases of anaphylaxis can occur within seconds or minutes of exposure and can be fatal if untreated, many reactions are milder and can be ended with prompt medical therapy. The term allergic rhinitis is the proper medical term for “hay fever.” The term allergic rhinitis is the proper medical term for “hay fever.” Rhinitis is inflammation of the nasal passages which can cause symptoms such as sneezing, itching, nasal congestion, runny nose, and postnasal drip (when mucus drains from the sinuses down the back of the throat). Most people develop symptoms of allergic rhinitis in childhood or young adulthood, though it can start at any age. At times patients will have no symptoms, and others will have them only certain times of the year. Symptoms are worst in children and adults in their 30s and 40s, though the severity of the symptoms varies throughout a person’s life. The class of drugs used treat to allergic reactions is called Antihistamines The class of drugs used treat to allergic reactions is called antihistamines. Your body releases substances called histamines which attach to cells in the body, causing them to swell and leak fluid. This results in common allergy symptoms such as itching, sneezing, runny nose, and watery eyes. Antihistamines help prevent or relieve allergy symptoms by preventing histamines from attaching to the cells and causing symptoms. Allergies can cause conjunctivitis. Allergies can cause conjunctivitis (pink eye), which is common in people who have other types of allergies such as hay fever, asthma, or eczema. Reactions to common allergens such as pollen, dust mites, animal dander, medications, cosmetics, and other allergy-provoking substances can result in allergic conjunctivitis. What is pet dander? Pet dander is the proper term for microscopic particles of skin shed by pets such as cats, dogs, rodents, birds, and any other animal with fur or feathers. In some people who are allergic to pet dander, these tiny flecks of skin can cause allergic reactions. In addition, proteins found in saliva, urine, and feces from cats, dogs, and other pets may trigger allergic reactions in some people. Pollen is a powder produced by certain plants that can trigger allergies. Pollen is a powder produced by certain plants that can trigger allergies. Throughout the year in the spring, summer, and fall, pollen is released into the air and carried by the wind to other plants to make seeds. This is how plants reproduce, but the pollen that travels in the wind is also in the air we breathe. For those who are allergic to it, it can trigger asthma and allergy symptoms. Celiac disease is caused by an autoimmune reaction to gluten. Celiac disease is a disease of the small intestine in which damage to the lining of the small intestine leads to malabsorption of minerals and nutrients. The destruction of the inner lining of the small intestine in celiac disease is caused by an immunological reaction to gluten, a family of proteins found in wheat, barley, rye, and oats. An allergic reaction can produce urticaria. A common term for urticaria is: Urticaria is the medical term for hives, a common allergic reaction that affects about 20% of people at some point in their lives. There are many triggers for hives, but the symptoms include itchy patches of skin that become swollen red welts. Itching can be mild to severe, and may be made worse by scratching, alcoholic beverages, exercise, and stress. Many people are aware of their triggers for hives, such as eating foods including shrimp or peanuts which cause the allergic reaction within a short time. For others, there are so many possible causes of hives it requires allergy testing by a physician. In a small number of cases the cause may never be identified.