Anaphylaxis is a potentially life-threatening condition that's most often a result of an allergic reaction. The most common culprits behind anaphylaxis are foods like peanuts, tree nuts, shellfish, dairy and eggs; medications like penicillin or aspirin; and stings from venomous insects like wasps, honeybees, hornets and yellow jackets. Anaphylaxis typically sets in a few minutes after you're exposed to the allergen, although it can take as long as a half-hour or more until you begin to experience symptoms.

The symptoms of anaphylaxis typically appear on your skin, in your breathing, in your stomach and in your circulatory system. On your skin, you may notice a rash, hives, swelling or itching; you might turn red or very pale. Anaphylaxis can also make your airways constrict, creating a difficulty breathing. You might find yourself coughing, wheezing, hoarse or with the feeling that there's a lump in your throat. It can be difficult to swallow and your throat might itch. Along with these symptoms, you may experience nausea, vomiting, cramps or diarrhea. Plus, your blood pressure will drop rapidly and your pulse will speed up, yet remain weak. You may feel dizzy or faint, and you might even lose consciousness. Some people have described a feeling of impending doom with anaphylaxis.

If you or someone near you experiences these symptoms, medical attention is required immediately. If you have an epinephrine autoinjector, it's meant for just such situations. Meanwhile, call for an ambulance. Paramedics can stop or slow anaphylaxis with epinephrine, intravenous antihistamines and steroids. Sometimes, oxygen is required. Even if you give the epinephrine injection yourself and see the symptoms going away, you need to see a doctor immediately for follow-up care. When everything is calm, you should sit with a medical professional to figure out how to handle anaphylactic risk in the long term.