What is a severe allergy?
过敏会对人的影响不同。虽然一个人可能会对某种过敏原产生温和的反应，但其他人可能会出现更严重的症状。轻度过敏是不便的，但严重的过敏可能会危及生命。
The substances that causeallergies称为过敏原。虽然pollen，，，，尘螨， 和霉菌孢子are common allergens, it’s rare for a person to have a severe allergy to them, because they’re everywhere in the environment.
可能的严重过敏原包括：
这些食物导致most allergic reactions：
轻度过敏症状可能不是极端的，但会影响整个身体。轻度症状可能包括：
- 皮疹
- hives
- 流鼻涕
- 眼睛痒
- nausea
- stomach cramping
严重的过敏症状更为极端。肿胀caused by the allergic reaction can spread to the throat and lungs, leading to过敏性哮喘或严重的状况被称为anaphylaxis。
随着时间的流逝，一些童年过敏会变得不那么严重。对于鸡蛋过敏尤其如此。但是，大多数过敏症一生都持续下去。
您还可以由于反复接触毒素而产生过敏，例如蜜蜂叮orpoison oak。With enough cumulative exposures over a lifetime, your immune system can become hypersensitive to the toxin, giving you a severe allergy.
Allergy symptoms occur when your immune system overreacts to allergens in your body. Your immune system mistakenly believes that an allergen from a food, such as a peanut, is a harmful substance invading your body. The immune system releases chemicals, including histamine, to fight off the foreign invader.
When your immune system releases these chemicals, it causes your body to have an allergic reaction.
当免疫系统反应过度时，它会导致身体部位膨胀，尤其是这些：
- 嘴唇
- 舌头
- 手指
- 脚趾
If your lips and tongue swell too much, they can block your mouth and prevent you from speaking or breathing easily.
如果您的喉咙或气道也膨胀，可能会引起其他问题，例如：
- trouble吞咽
- trouble breathing
- shortness of breath
- 喘息
- 哮喘
抗组胺药andsteroidscan help bring the allergic reaction back under control.
当肺中的微小结构发炎，导致它们肿胀并限制气流时，就会发生哮喘。因为过敏反应通常会导致肿胀，所以它们会触发一种称为哮喘的形式过敏性哮喘。
Allergic asthma can be治疗the same way as regular asthma: with a救援吸入器，含有溶液，例如沙丁胺醇（ACCUNEB）。Albuterol使您的气道扩展，从而使更多的空气流入您的肺部。但是，在过敏反应的情况下，吸入器并不能有效，因为过敏反应会关闭喉咙，从而阻止药物到达肺部。
当过敏性肿胀变得如此极端以至于使您的喉咙关闭，从而防止空气通过时，就会发生过敏反应。在过敏反应中，您的血压可能会下降，并且您的脉搏可能会变成弱或螺纹。If the swelling restricts airflow for long enough, you can even fallunconscious。
If you think you’re starting to experience anaphylaxis, use an epinephrine (adrenaline) injector, such asEpipen，，，，Auvi-Q，或肾上腺素。肾上腺素有助于打开呼吸道，使您再次呼吸。