Allergies

Allergies are your immune system's reaction to substances your body perceives as harmful, called allergens. When your body senses an allergen, it produces antibodies that release chemicals into the bloodstream (histamine is the most prevalent of these chemicals), which cause the symptoms of an allergic reaction, usually focused in the eyes, nose, throat, lungs, skin, and gastrointestinal tract.

Allergies are among the most common types of chronic illness in the United States, affecting more than 35 million Americans. A person can develop an allergy at any age.

Allergies are not only bothersome, but many have been linked to a variety of common and serious chronic respiratory illnesses (such as sinusitis and asthma). Additionally, allergic reactions can be severe and even fatal.

The symptoms are not contagious, but only vary slightly from the common cold, which is contagious. Normally, the immune system responds to foreign micro organisms, or particles, like pollen or dust, by producing specific proteins, called antibodies, that are capable of binding to identifying molecules, or antigens, on the foreign particle.
Allergies are genetic; if one parent has allergies, their child is 30% more likely. If both parents have allergies, their child is more than 60% likely to develop allergies.
Allergic individuals should wear dust masks. Allergies to plants often cause skin rash. Drug allergies usually involve the whole body. Allergies and hypersensitivity to certain substances are considered immune system disorders. In addition, the immune system plays a role in the rejection process of transplanted organs or tissue.
Allergic symptoms typically occur when allergy sufferers are in situations that put them in close contact with allergens to which they are sensitive, such as mowing the lawn, spending time outdoors or playing with pets.
Allergy testing may be needed to determine if the symptoms are an actual allergy or caused by other problems. For example, eating contaminated food (food poisoning) may cause symptoms similar to food allergies. Allergy symptoms can lessen as you get older, but they rarely completely disappear.
Allergic reactions of the skin can have many possible causes. Examples of irritants that can cause allergic reactions when they touch your skin are hair or skin care products, nickel in jewellery and belt buckles, dyes in leather or fabric, and poison ivy or poison oak. Allergies occur in response to normally harmless triggers known as allergens. The body of a person with an allergy responds to an allergen by attacking it.
Symptoms of food allergy include abdominal pain, bloating, vomiting, diarrhoea, itchy skin, and swelling of the skin during hives. Food allergies rarely cause respiratory (asthmatic) reactions, or rhinitis. Symptoms may include mild to intense itching and chewing of the skin, irritation and inflammation of the skin, hair loss, sores on the skin, and sometimes sneezing, or irritated eyes with discharge.
Symptoms like hay fever, eczema, or asthma indicate allergies, while migraine, digestive problems, and behaviour problems indicate intolerance. These reactions are not common affecting under 10% of babies and even fewer children, however food intolerance is much more common and goes undiagnosed much more frequently.
Skin allergies like those attributed to dust mites and pollens can be severe, but there is allergy testing which can be done to determine exactly what you are allergic to.
If it is proven that you have allergies to dogs or cats or pollens, you can take allergy shots as a form of treatment and try to build up your tolerance to them.
Skin and blood tests for IgE against specific foods only detect true food allergies; the tests don’t detect other kinds of immunologic reactions or food intolerances, which may require other tests.
Skin tests cannot predict if a reaction would occur or what kind of reaction might occur if a person ingests that particular allergen. They can however confirm an allergy in light of a patient's history of reactions to a particular food.
Skin tests are more accurate for pollen, dust, and insect bites, than for food and medications. Food allergies are usually quite complex and skin test diagnosis is therefore less accurate. Skin testing can sometimes detect which substance causes the reaction.
Medications such as pills or nasal sprays are often used to treat allergies. Although medications can control the allergy symptoms (such as sneezing, headaches, or a stuffy nose), they are not a cure and can't make the tendency to have allergic reactions go away.
Asthma, allergy, and atopy are all a type of immune dysfunction known generally as type I hypersensitivity. Its determinants are partly genetic, partly environmental. Asthma affects millions of people. The attacks can be mild, moderate, severe or life threatening.