It is a severe, whole-body allergic-type reaction. This is often because of an allergen. An allergen is something that can cause an allergic reaction. For example, if you are exposed to bee sting venom, your immune system might become sensitized to it. When the you are exposed to it again, you may have an allergic reaction. This can happen quickly after your exposure, within seconds or minutes and up to a few hours. Different parts of your body can release histamine and other substances which leads your symptoms.
You can get anaphylaxis from any allergen, such as:
Pollen and other inhaled allergens rarely cause anaphylaxis, but some cases can seem like it.
Some people have a reaction with no known cause. This may be autoimmune-like.
These can start quickly, often within seconds or minutes. They can be:
Hives, itchiness, redness of the skin
Swelling of the face, eyes, or tongue
Chest discomfort/tightness, shortness of breath, coughing, wheezing
Abdominal pain, nausea, vomiting, diarrhea
Dizziness or lightheadedness
Loss of consciousness
Exams and tests
You may need a physical exam to diagnose.
You may get blood and allergy testing to help find the cause. This is if it is not known already.
You need medical attention right away. This is an emergency condition.
If you have any type of serious or whole-body reaction after eating the food:
Inject the epinephrine.
Go to the nearest hospital or emergency facility right away.