In an allergic reaction, the immune system recognizes a normally harmless substance, called an allergen, as harmful, and releases the antibodies Immunoglobulin E (IgE). Allergens may be anything from foods, to pollen, to animal hair. The IgE tells the cells to produce histamine, which causes itching and swelling. These reactions occur in the cells of the body that are exposed to the allergen, often the mouth, lips, throats, lungs, digestive system, or skin. When having an allergic reaction, people may take antihistamines such as Benadryl or Zyrtec, or oral steroids. Allergic reactions have varying severity. Severe, anaphylactic reactions can be life threatening. In such cases, an epipen must be used.
While there is no known cause of most allergies, they are linked with asthma, eczema, and other immune responses. Rates of allergies are increasing, and may be attributed to environmental and chemical factors, such as the increased rate of antibiotics. There has been a recent uptick in mammalian meat allergy, a rare allergy thought to be caused by tick bites.
While there is no definite “cure” for all allergies, some people do immunotherapy to alleviate them. In immunotherapy, patients are injected with a small amount of the allergen, which is slowly and over time increased until the person is desensitized to the allergen, much like with vaccines. Once immunity is built up, it must be maintained. There are also oral immunotherapies, where a tiny amount of the food is eaten in gradually increasing doses to build tolerance. Additionally, taking probiotics can also help with severity of allergies.