Anaphylaxis

A severe allergic reaction (anaphylaxis) can produce shock and life-threatening respiratory distress. In sensitive people, anaphylaxis can occur within minutes or up to several hours after exposure to a specific allergy-causing substance. Almost any allergy-causing substance — including insect venom, pollen, latex, certain foods and drugs — can cause anaphylaxis. Some people have anaphylactic reactions from unknown causes.
If you're extremely sensitive, you might break out in hives, and your eyes or lips might swell severely. The inside of your throat might swell as well, even to the point of causing difficulty breathing and shock. Dizziness, mental confusion, abdominal cramping, nausea, vomiting or diarrhea also may accompany anaphylaxis.
If you've had an anaphylactic reaction in the past, carry medications with you as an antidote. Epinephrine is the most commonly used drug for severe allergic reactions. It comes only as an injection that must be prescribed by your doctor. You should also carry an antihistamine pill, such as cetrizine(Cetzine, others), because the effects of epinephrine are only temporary. Seek emergency medical attention immediately after taking these medications.
Anaphylaxis is a life-threatening medical emergency because of rapid constriction of the airway, often within minutes of onset, which can lead to respiratory failure and respiratory arrest. Brain and organ damage rapidly occurs if the patient cannot breathe. Due to the severe nature of the emergency, patients experiencing or about to experience anaphylaxis require the help of advanced medical personnel. First aid measures for anaphylaxis include rescue breathing (part of CPR). Rescue breathing may be hindered by the constricted airways, but if the victim stops breathing on his or her own, it is the only way to get oxygen to him or her until professional help is available.
Another treatment for anaphylaxis is administration of epinephrine (adrenaline). Epinephrine prevents worsening of the airway constriction, stimulates the heart to continue beating, and may be life-saving. Epinephrine acts on Beta-2 adrenergic receptors in the lung as a powerful bronchodilator (i.e. it opens the airways), relieving allergic or histamine induced acute asthmatic attack or anaphylaxis. If the patient has previously been diagnosed with anaphylaxis, they may be carrying an EpiPen (or TWINJECT TM) for immediate administration of epinephrine. However, use of an EpiPen or similar device only provides temporary and limited relief of symptoms.