Allergy is characterized by an overreaction of the human immune system to a foreign protein substance "allergen" that is eaten, breathed into the lungs, injected or touched. This immune overreaction can results in symptoms such as coughing, sneezing, itchy eyes, runny nose and scratchy throat. In severe cases it can also result in rashes, hives, lower blood pressure, difficulty breathing, asthma attacks, and even death. Both genes and environment play a role. If both parents have allergies, there is a chance of occurring to the child too.
When it recognizes an allergen, the immune system launches a response. Chemicals such as histamines are released. These chemicals cause allergy symptoms. Allergens that you breathe in often cause a stuffy nose, itchy nose and throat, mucus, cough, and wheezing. Eating something are allergic to can cause nausea, vomiting, abdominal pain, cramping, diarrhea, or a severe, life-threatening reaction. Allergens that touch the skin can cause a skin rash, hives, itching, blisters, or skin peeling.
Severe allergic reactions need to be treated with a medicine called epinephrine. It can be life-saving when given right away. The best way to reduce symptoms is to avoid what causes allergies. This is especially important for food and drug allergies. There are several types of medications to prevent and treat allergies. Medicine that is recommended depends on the type and severity of symptoms, age and overall health.