Anaphylaxis is a severe allergic reaction. It can lead to a potentially fatal condition known as anaphylactic shock.
Common substances that the body reacts to include food, insect bites, venom, and medication. These are called allergens.
Food allergy is the main cause of anaphylaxis outside of the hospital, according to Food Allergy Research and Education (FARE).
Anaphylactic reaction to food is responsible for one emergency department visit every 3 minutes in the United States (U.S.), mostly in teenagers and young adults.
The most common triggers are medications, foods, and insect stings.
What happens in anaphylaxis?
Many people react to a substance, or allergen, with watery eyes, a runny nose, and maybe a rash. However, a severe allergic reaction can lead to a serious condition known as anaphylaxis. Anaphylaxis happens when the body reacts badly to a substance, or allergen, as if it were a threat to health, like bacteria or a virus. The body produces large amounts of histamine, and this triggers an inflammatory response. This response can lead to a dilation of the blood vessels, a sudden drop in blood pressure, loss of consciousness, and shock. As the airways narrow, breathing becomes difficult. The blood vessels may leak, resulting in edema, or swelling, in surrounding tissue. The reaction may happen at once, within hours, or, very occasionally, some days after coming into contact with the allergen.
It is important to know the signs and symptoms of anaphylaxis, because urgent action may be needed. They include: difficulty breathing, wheezing, shortness of breath, tightness in the throat and chest pain trouble swallowing a cough and a hoarse voice itchy mouth or throat and nasal congestion feeling that something is stuck to the tongue, or in the throat a full and heavy feeling in the tongue swelling and itchiness on the skin, with hives, warmth, redness, and a rash stomach pain and cramps, with nausea, vomiting, and diarrhea anxiety and a feeling of impending doom swelling of the feet, hands, lips, eyes, and sometimes the genitals low blood pressure and poor circulation leading to pale blue skin, a low pulse, dizziness, or faintness shock loss of consciousness The person may also have itchy, red, watery eyes, a headache, and cramping of the uterus. They may have a metallic taste in the mouth. Severe breathing difficulties, a serious drop in blood pressure, or both can lead to shock, and this can be fatal.
Anaphylaxis is a life-threatening emergency. People who are most susceptible to it are those with allergies. However, it is not always predictable. Some people react to a substance that has not affected them previously. After having an allergic reaction, the person should remember what caused it, and try to avoid it in future. As it is not always possible to avoid an allergen, they may need to carry an injector and wear a bracelet to let other people know that they have an allergy People should let their friends, employers, or school staff know about any allergies that could cause a severe reaction. Anaphylaxis is a potentially life-threatening emergency that needs immediate assistance. Everyone should know the signs and symptoms, and how to react.