What is an Anaphylactic Reaction?

An anaphylactic reaction is a sudden, life-threatening immune system response to an allergen. While most allergic reactions result in relatively minor rashes or sinus problems, an anaphylactic reaction causes full-body hives, mental confusion, and severe airway constriction. Immediate medical attention is needed after a reaction occurs to prevent potentially fatal complications.

An allergic reaction occurs when the immune system mistakenly recognizes a foreign substance as a threat to a person's health. The immune system releases chemicals called histamines to combat the foreign particles, which leads to inflammation, swelling, and mucus production. In the case of an anaphylactic reaction, histamines are produced and released in massive quantities, flooding the bloodstream and penetrating body tissue.

Any allergen can potentially produce an anaphylactic reaction in a severely allergic person. The most common triggers are food products, including nuts and fish, insect stings, and medications such as penicillin. An anaphylactic reaction can occur within minutes or even seconds after coming into contact with an allergen. Common symptoms include the development of itchy hives all over the body, nausea, dizziness, and low blood pressure. Swelling of the face and extremities is likely, and inflammation in the throat and tongue can cause serious breathing difficulties.

An individual may become confused, turn pale, and even faint when he or she cannot breathe in an adequate amount of oxygen. Without immediate treatment, a person may go into shock or experience cardiac arrest. When an anaphylactic reaction occurs, bystanders should call an ambulance right away and monitor the sufferer to make sure he or she keeps breathing. Cardiopulmonary resuscitation may be necessary while waiting for emergency responders to prevent respiratory failure.

After confirming that an anaphylactic reaction has occurred, an emergency responder provides an injection of epinephrine, a hormone that helps to raise blood pressure and reopen the airways. The patient is then given oxygen and intravenous fluids to prevent shock and transported to a hospital. Once blood pressure returns to normal and vital signs are stable, doctors can provide oral or intravenous antihistamines to fully stop the immune system's response. The patient is usually kept in the hospital for several days so doctors can monitor his or her condition.

Following treatment, doctors and nurses can work with the patient to determine what caused the anaphylactic reaction and learn how to prevent future problems. Foremost, a patient is instructed to stay away from his or her trigger if at all possible. Many patients are given their own emergency supply of epinephrine and an injector to use in an emergency situation.