为什么我的过敏会随着年龄的增长而改变?

为什么我的过敏会随着年龄的增长而改变?

If we were to sum up allergies with an emoji, it’d be a shrug. We know so little about them, and yet tens of millions of Americans experience allergies of some kind or another throughout their lives.

如果我们用一个表情符号来总结过敏，那就是耸肩。我们对它们知之甚少，但仍有成千上万的人在他们的一生中经历着这样或那样的过敏。

But there is some positive news for allergy sufferers everywhere.

但对各地的过敏患者来说，有一些好消息。

The only good thing about getting older is that​,​ in many cases, allergies are less prevalent, says Clifford Bassett, medical director of Allergy & Asthma Care of NY and an allergy specialist at New York University. Changes inside and outside our bodies as we age affect the way we react to potential irritants from ragweed to crab to dogs. Why? Well, that's a little more complicated, and there's more than one possible reason that your allergy status just switched.

“变老的唯一好处是，在很多情况下，过敏不那么普遍了。”纽约过敏与哮喘护理中心的医学主任、纽约大学(New York University)过敏症专家克利福德·巴塞特(Clifford Bassett)说。随着年龄的增长，我们体内外的变化会影响我们对豚草，螃蟹到狗等潜在刺激物的反应方式。为什么?这就有点复杂了，你的过敏状况改变的原因可能不止一个。

You outgrew it

你长大了

Around 60 to 80 percent of kids with milk and egg allergies outgrow them by age 16. Only 20 percent of kids with peanut allergies do so, and only 14 percent of those allergic to tree nuts. Just 4 or 5 percent outgrow a shellfish allergy.

大约60%到80%对牛奶和鸡蛋过敏的孩子到16岁就会痊愈。对花生过敏的孩子中只有20%会痊愈，而对树坚果过敏的孩子中只有14%会痊愈。只有4%或5%的人不再对贝类过敏。

Why? Unfortunately, the answer is that we mostly have no idea. We know some general associations—the earlier a child has an adverse reaction to food, the more like they are to outgrow it—but scientists don't yet understand why some kids age out of their reactions and others don't. We do know that early exposure to small amounts of food allergens, especially peanuts, helps prevent allergies in the first place. But we have no idea how to actively reverse them once they happen. If you get allergies as a kid, you just have to wait and see if your tolerances change in the future.

为什么?不幸的是，答案是我们大多不知道。我们知道一些普遍的关联——孩子对食物的不良反应越早，他们长大后就越有可能克服——但是科学家们还不明白为什么有些孩子对食物的不良反应早于其他孩子。我们知道，早期接触少量食物过敏原，尤其是花生，有助于预防过敏。但我们不知道一旦它们发生，如何积极地逆转它们。如果你小时候有过敏症，你只需要等待，看看你的耐受性在未来是否会改变。

One of the few things researchers have observed is that there does seem to be a time limit to ridding yourself of childhood allergies—if you haven’t outgrown an allergy by your teens, you’re likely to have it for life.

研究人员观察到的为数不多的事情之一是，摆脱儿童过敏似乎是有时间限制的——如果你在十几岁时还没有摆脱过敏，你很可能会终生过敏。

You're moving to new places

你搬到了新的地方

Allergies, especially the seasonal variety, can change a lot over a lifetime, but it might not have anything to do with your body. Every place you live has its own set of allergens, so moving from one town to the next will likely change your allergies too. Teens moving out of their parents' houses or adults changing jobs may experience a sudden surge of allergies, or sweet, sneeze-less relief.

过敏，尤其是季节性过敏，在人的一生中会发生很多变化，但它可能与你的身体没有任何关系。你住的每个地方都有自己的过敏原，所以从一个城镇搬到另一个城镇可能也会改变你的过敏反应。从父母家里搬出来的青少年或换工作的成年人可能会突然出现过敏症状，或出现愉快的、打喷嚏少的症状。

It also takes time to become allergic to things. You may not feel a reaction to ragweed during your first summer in Tennessee, but have a full-blown allergy the next. That’s because you became sensitized one year and reacted the next. Similarly, you may visit someone with a dog and seem fine, but sneeze constantly the next time you hang out at their home.

对事物过敏也需要时间。在田纳西州的第一个夏天，你可能对豚草没有任何反应，但在接下来的一个夏天，你就会完全过敏。那是因为你一年变得敏感，第二年就反应了。同样的，你可能会带着狗去拜访某人，看起来很好，但是下次你在他们家玩的时候，你可能会不停的打喷嚏。

You're just allergy-prone

你只是容易过敏

Some people are just unlucky. Again, we have no idea why, but clearly a subset of humans have immune systems primed to identify allergens as potential dangers, giving those poor folks a whole host of allergies while others go sneeze-free. People with one allergy are far more likely to develop another, and as far as we can tell there's no way to avoid that unless you prevent exposure altogether. And since most of us don't want to live in bubbles, that means allergy-prone folks are likely to suffer the sniffles their whole lives.

有些人就是不走运。同样，我们也不知道为什么，但很明显，一部分人的免疫系统已经准备好识别潜在危险的过敏原，当其他人都不打喷嚏的时候，这些人却对很多东西过敏。有一种过敏的人更有可能发展另一种过敏，据我们所知，除非你完全避免接触，否则无法避免。因为我们大多数人都不想生活在泡泡里，这就意味着容易过敏的人可能一生都要忍受鼻塞的折磨。

This is distinct, however, from atopy. Atopy is a genetic predisposition to acquiring allergies that essentially means that nearly everything you come in contact with allergen-wise will become a full-blown allergy. Getting a dog? You’ll be allergic soon. Moving house? Enjoy the new outdoor allergies. Atopic people are also more likely to have eczema and asthma. Corticosteroids can sometimes help, as can allergy shots, but it’s still often a lifelong affliction.

然而，这与特异反应是不同的。特异反应性是一种遗传易感性，本质上意味着几乎所有你接触到的过敏原都会变成全面过敏。养狗?您很快就会过敏。搬家?享受新的户外过敏。特应症患者更容易得湿疹和哮喘。皮质类固醇有时会有帮助，过敏针也会有帮助，但它仍然是一种终生的折磨。

Your body is changing

你的身体在变化

The link between hormones and allergies haven't been well studied, but some small studies and anecdotal evidence suggest that your immune system can shift a bit in response to hormonal changes. Like nearly everything hormone-related, this affects people with menstrual cycles the most. "In women, the effect of hormones​,​ such as estrogen​,​ may lead to ​a ​worsening of their asthma during different​ times of the menstrual cycle," explains Bassett. Puberty, pregnancy, and menopause are also commonly times of allergic change—at least anecdotally, since few studies on the subject exist in the literature. Asthma symptoms definitely change during these shifts in hormonal balance, and female bodies experience more autoimmune diseases and immune responses generally, which seems to indicate that female sex hormones have a significant influence on the immune system.

激素和过敏之间的联系还没有得到很好的研究，但一些小型研究和轶事证据表明，你的免疫系统可能会对激素的变化做出一些改变。就像几乎所有与荷尔蒙有关的东西一样，月经周期的人受到的影响最大。“在女性中，激素的作用，比如雌激素，可能会导致她们在月经周期的不同时期哮喘的恶化。”Bassett解释说。青春期、怀孕和更年期也是过敏改变的常见时期——至少在轶事中是这样，因为文献中很少有关于这方面的研究。在这些激素平衡的变化过程中，哮喘的症状肯定会发生改变，女性身体普遍会经历更多的自身免疫性疾病和免疫反应，这似乎表明女性性激素对免疫系统有显著的影响。

Bassett also notes that factors like weight gain and obesity can affect your immune system, leading to less well controlled asthma and other allergy symptoms over time. Older adults also tend to have a drop off in the kind of antibodies that instigate allergic responses, which means they may lose their reaction to a food or pollen that they used to react to powerfully. But simultaneously, lots of seniors seem to lose tolerance to foods like shellfish, even if they’d previously been able to eat crab every single day.

巴塞特还指出，体重增加和肥胖等因素可能会影响您的免疫系统，导致长期控制的哮喘和其他过敏症状的缓解。老年人也容易引起过敏反应的抗体种类下降，这意味着他们可能会失去对食物或花粉的反应，而这些食物或花粉通常会对其产生强烈的反应。但与此同时，即使他们以前每天都能吃螃蟹，许多老年人似乎对诸如贝类的食物也失去了抵抗力。