Why do people have seasonal allergies? - Eleanor Nelsen

譯者: Ann Chen 審譯者: Max Chern

Ah, spring.

啊！春天

Grass growing, flowers blooming, trees growing new leaves,

綠草滋生，百花齊放，樹長新葉

but if you get allergies,

但如果你患了過敏症

this explosion of new life probably inspires more dread than joy.

對這些新生命的激增 可能產生的恐懼多於歡樂

Step outside, and within minutes, you're sneezing and congested.

走出戶外，只消幾分鐘 你就打噴嚏及鼻塞

Your nose is running,

流鼻水

your eyes are swollen and watery,

眼睛腫脹且淚汪汪

your throat is itchy.

喉嚨發癢

For you and millions of others, it's seasonal allergy time.

對你及數百萬的其他人而言， 過敏症的季節到了

So what's behind this onslaught of mucus?

這種突如其來 大量黏液的原因是什麼呢？

The answer lies within you.

答案就在你體內

It's your immune system.

就是你的免疫系統

Seasonal allergies, also called hay fever, or allergic rhinitis,

季節性過敏 ── 也稱為「花粉熱」或「過敏性鼻炎」

are a hypersensitive immune response to something that's not actually harmful.

是一種對無害物質的過敏免疫反應

Pollen from trees and grass,

來自樹與草的花粉

and mold spores from tiny fungi find their way into your mucous membranes

及微小霉菌孢子進入你的粘膜

and your body attacks these innocuous travelers

你的身體攻擊這些無害的過路者

the same way it would infectious bacteria.

採取對抗細菌感染一樣的方式

The immune system has a memory.

免疫系統具有記憶

When a foreign substance gets tagged as threatening,

當外來物被貼上 ‘具威脅性’ 的標籤

white blood cells produce customized antibodies

白血球會製造特定的抗體

that will recognize the offender the next time around.

於下一次辨識這個入侵者

They then promptly recruit the body's defense team.

如此可迅速地動員身體的防衛成員

But sometimes, the immune system accidentally discriminates

但有時，免疫系統會無意地

against harmless substances, like pollen.

排斥一些無害物質，如花粉

When it wafts in again, antibodies on the surface of white blood cells

當它再次飄入，白血球表面的抗體

recognize it and latch on.

會辨識出並抓住它

This triggers the cell to release inflammatory chemicals,

這會誘發細胞釋放發炎化學物質

like histamine,

如組織胺

which stimulate nerve cells,

它會刺激神經細胞

and cause blood vessels in the mucous membranes to swell and leak fluid.

並造成粘膜的血管腫脹及滲出液體

In other words, itchiness, sneezing, congestion, and a runny nose.

也就是發癢、打噴嚏、 鼻塞和流鼻水

Allergies usually, but not always, show up for the first time during childhood.

過敏症通常（但並非總是） 第一次是出現在孩童時期

But why do some people get allergies and others don't?

但為何有些人會過敏， 而其他人不會呢？

Allergies tend to run in families, so genetics may be one culprit.

過敏症大都有家族的傾向， 所以基因可能是一個起因

In fact, errors in a gene that helps regulate the immune system

事實上，協助調節免疫系統 的基因發生錯誤

are associated with higher rates of allergies.

與過敏症的較高發生率有關

The environment you grow up in matters, too.

你成長的環境也有關

Being exposed to an allergen as a baby

當嬰兒時期曝露於某一過敏原時

makes you less likely to actually develop an allergy to it.

讓你較不會對它產生過敏

People who grow up on farms,

生長在農場、大家族

in big families,

and in the developing world also tend to have fewer allergies,

及開發中國家的人也較少有過敏症

although there are plenty of exceptions, partly thanks to genetics.

雖然有許多例外，一部分是由於遺傳

One theory is that as children,

有一理論是說當孩童時

they encounter more of the microbes and parasites

他們接觸較多微生物與寄生蟲

that co-evolved with traditional hunter-gatherer societies.

牠們是與傳統捕獵社會共同演化的

Called the hygiene hypothesis,

這想法稱為 「衛生假說」 (hygiene hypothesis)

the idea is that when the immune system

也就是當免疫系統

isn't exposed to the familiar cast of microbes,

沒有曝露於常見的微生物種類下

it'll keep itself busy mounting defenses against harmless substances,

它反而會忙於 對無害物質建立防衛機制

like pollen.

如花粉

Another theory is that an immune system toughened up by a barrage of pathogens

另一個理論是受病原體猛攻後 所強化的免疫系統

is less likely to overreact to allergens.

對過敏原較不會過度反應

Pollen is a common offender, just because we encounter so much of it,

花粉是一種常見的肇事者， 只是因為我們經常接觸它

but there's a long list of substances:

但有許多的物質：

dust,

灰塵

animal dander,

動物皮毛

insect venom,

昆蟲毒素

medications,

藥物

certain foods,

某些食物

that can send your immune system into overdrive.

能讓你的免疫系統忙個不停

Some of these reactions can be scary.

這其中一些反應會非常嚇人

An allergy can develop into full-blown anaphylaxis,

過敏能演變成 全身性過敏性反應（anaphylaxis）

which typically brings on severe swelling,

通常引起嚴重的腫脹

shortness of breath,

呼吸困難

and very low blood pressure.

及非常低的血壓

It can be deadly.

它可能會致命

The body can even have an allergic reaction to itself

身體甚至可能對自己產生過敏反應

causing auto-immune disorders,

導致「自體免疫性疾病」

like multiple sclerosis, lupus, and type 1 diabetes.

如多發性硬化症、 紅斑性狼瘡及第一型糖尿病

But even non-life threatening allergy symptoms can make you miserable,

但即使無生命威脅的過敏症狀 也會使你難過至極

so what can you do about it?

那你該如何處理呢？

Medications can help reduce the symptoms.

藥物能幫助緩解症狀

The most common ones keep histamines from binding to your cells.

最常用的藥是 避免組織胺與細胞結合

These antihistamines stop the inflammation response.

這些抗組織胺藥物可抑制發炎反應

Steroids can help dial down the immune system.

類固醇能幫助減低免疫系統反應

Another more permanent option is immunotherapy.

另一種較持久的方法是「免疫療法」

Deliberate, controlled exposure

審慎且可掌握地曝露在

to gradually increasing amounts of an allergen

一種過敏原，且逐漸增加劑量

can teach the immune system that it isn't dangerous after all.

能毫無危險地教導免疫系統

And if you're really adventurous, there's a less traditional option:

假如你真的愛冒險， 有一個非正統的方法：

intestinal parasites.

腸道寄生蟲

When hookworms sink their teeth into the intestinal wall,

當鉤蟲將牙齒插入腸壁

they secrete chemicals that blunt the immune system.

會分泌化學物質，減弱免疫系統

Some studies suggest that hookworms can treat allergies,

有些研究指出鉤蟲能治療過敏

which may be another reason

這可能是過敏症常見於 工業化國家的另一原因

allergies are more common in industrialized countries

where hookworms are few and far between.

鉤蟲在那兒是稀少而罕見的

Of course, you can always just wait your seasonal allergies out.

當然，你可以等待季節性過敏結束

The spring pollen onslaught dwindles by mid-summer,

仲夏前，春天花粉的激增會逐漸減少，

just in time for ragweed season.

剛剛好進入秋天豚草的季節 （也會導致過敏性鼻炎）

翻譯：Ann Chen