Anaphylaxis is a Type of Severe Allergic Reaction

Certain allergens can cause a severe allergic reaction. Symptoms of anaphylaxis appear very quickly, after only a few seconds or minutes, after exposure to the allergen. Sometimes it appears after 2 to 4 hours, and extremely rarely after 12 hours after exposure to the substance that causes it. The patient feels swelling, itching or notices a rash on the skin. Some people begin to have difficulty breathing, suffocate or become unsteady. A certain group of people notice abdominal cramps, nausea or diarrhea. Some people also lose consciousness.