an extreme and dangerous allergic reaction to something that a person has eaten or touched

In severe cases, anaphylaxis - the swelling of the tongue and closing of the throat - can occur and is life-threatening. 情况严重时会发生过敏性反应，如舌头肿大和喉咙闭塞等，有生命危险。

Scientists believe a bite from a tick can lead to anaphylactic shock. 科学家相信被壁虱咬了可能会导致过敏性反应休克。