Article in English: . Anaphylaxis can occur when a person is accidentally exposed to a known allergen, but it also can occur when a person is exposed to an allergen for the first time. It is also possible to become sensitized to an allergen, that is,  to develop allergies to things that previously did not cause a reaction.  In some cases the reaction can be so severe it can be life threatening. Look for the following symptoms:  Flushing of the skin Rash on the body Swelling of the throat and mouth Difficulty swallowing and speaking Severe asthma Abdominal pain Nausea and vomiting Drop in blood pressure Collapse and unconsciousness Confusion, dizziness or an "impending sense of doom" Anaphylaxis is considered a 'treat first' emergency. If the person knows they need an injection and can inject themselves, ensure they do so before calling emergency services. If they need you to inject them, the instructions for the EpiPen are printed on the side of the device. . Even if the person feels fine after injecting epinephrine/adrenaline, it's still imperative to have professional help as soon as possible. The EpiPen will only last for as long as it takes emergency services to reach you.  Always have your country's emergency number on your phone. In the U.S. and Canada, the emergency number is 911. In the UK, 999 is the main emergency number. In Australia, dial Triple Zero (000).  Tell the operator your location before anything else, so help can be sent immediately. Describe the condition and the emergency to the operator. If you suspect a case of anaphylaxis in someone else, look for a necklace or bracelet. People suffering from severe allergies usually carry those in case of an accident.  These necklaces and bracelets detail the condition and give additional information on health. They usually bear a Red Cross sign or other easily recognizable visual clues. If you suffer from severe allergies, always carry the instructions with the EpiPen. That way, if you are incapacitated and someone else has to administer it, they'll know what to do....

Summary in Chinese:
确定过敏反应的症状。 询问患者是否需要帮助。 呼叫紧急医疗服务。 查看患者随身携带的医疗ID项圈或手链。