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.
Fast facts about anaphylaxis
Anaphylaxis is a severe allergic reaction.
It can cause breathing problems, plummeting blood pressure, shock, and potentially death.
Anaphylactic reactions to allergens in food cause one hospital visit every 3 minutes in the U.S.
An adrenalin shot, such as from an EpiPen, can help to stop the progression of symptoms.
Avoiding known allergens can reduce the risk of anaphylaxis. However, if an allergen has never caused reaction before, there is no way to prepare for its anaphylactic reaction.
What happens in anaphylaxis?
Anaphylaxis can have a fatal outcome unless signs are quickly responded to.
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.
difficulty breathing, wheezing, shortness of breath, tightness in the throat and chest pain
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
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.
If a person starts to show severe allergic symptoms, urgent medical attention is needed.
First aid for anaphylaxis includes:
removing the allergen, if possible, and calling for emergency assistance
finding out if the patient has a history of allergy
helping them administer any medication they may have
reassure the patient so that they feel comfortable