Allergy

An allergy is an allergic disease of the immune system. Allergic reactions occur to environmental substances called allergens normally harmless, and these reactions are acquired, predictable and fast. Strictly, allergy is one of four types of hypersensitivity and is called type I (or immediate) hypersensitivity. It is characterized by excessive activation of certain white blood cells called mast cells and basophils by a type of antibody called IgE, which causes an inflammatory response extreme. Common allergic reactions include eczema, hives, hay fever, asthma, food allergies and reactions to the venom of stinging insects such as wasps and bees. Mild allergies like hay fever is widespread in the symptoms of the population and a cause such as allergic conjunctivitis, itching and runny nose. Allergy may play an important role in conditions such as asthma.In some people, severe allergies to environmental allergens or food or drugs can lead to anaphylactic reactions, life-threatening.

A variety of tests now exist for the diagnosis of allergic disease, these tests include skin responses to known allergens or analyzing the blood of the presence and levels of allergen-specific IgE. The treatment for allergies is to avoid the allergen, the use of antihistamines, steroids or other oral medications, immunotherapy to desensitize the response to the allergen, and targeted therapy.

Signs and symptoms

Many allergens such as dust or pollen, are airborne particles. In these cases, symptoms occur in areas exposed to air, such as eyes, nose and lungs. For example, allergic rhinitis, also known as hay fever, nasal irritation, sneezing and itching and redness of the eyes. Inhaled allergens can also cause asthma symptoms caused by stenosis Airways (bronchoconstriction) and increased production of mucus in the lungs, shortness of breath (dyspnea), coughing and wheezing.

In addition to these environmental allergens, allergic reactions can be caused by foods, insect stings and reactions to medications such as aspirin and antibiotics such as penicillin. The symptoms of food allergy include abdominal pain, bloating, vomiting, and diarrhea, itching and swelling of the skin of the skin during hives. Food allergies rarely cause respiratory (asthma), reactions, or rhinitis. insect stings, antibiotics and some drugs cause systemic allergic reaction, which is also called anaphylaxis; organ systems may be affected, such as the digestive system, respiratory system and circulatory system. Depending on the speed of gravity can cause skin reactions, bronchoconstriction, edema, hypotension, coma and death. This type of reaction can be triggered suddenly or the onset may be delayed. The severity of the allergic reaction often requires the injection of epinephrine, sometimes the device is known as EpiPen or Twinject auto-injector. The nature of anaphylaxis is such that the reaction may seem like failure, but may recur over a prolonged period.

Substances that come into contact with skin, such as latex, are also common causes of allergic reactions, contact dermatitis or eczema. Skin allergies frequently cause rashes, or swelling and inflammation in the skin, in what is known as a reaction characteristic wheal and rash of urticaria and angioedema.