預防過敏症的對策

在預防過敏症方面可分以下三大類：

1.          完全沒有過敏症狀的嬰兒或小童，可怎樣防止過敏症發生？

2.          已經患有某種過敏症如鼻敏感、食物敏感，或濕疹的小童，能否避免產生其他的過敏病？

3.          已經患有過敏症如哮喘的小童，又如何防止他們病發？

家族史過敏症的先知

在過往的研究中得知，過敏症的先兆是對某些致敏原出現過敏跡象，舉例大部份哮喘患者發病前，首先會對塵蟎或貓狗等有過敏反應，繼而是鼻敏感和哮喘。不過，若嬰兒未出現過敏症前又怎樣知道將來患上的機會？此時便要計算嬰兒的家族史；若父母雙方同是過敏症患者，嬰兒日後患有過敏症的機會比一般的小童高，亦即是高危一族。

臍帶血有效的過敏指標

另一方法是嬰兒在出世時取臍帶血化驗。若臍帶血中的IgE抗體高出正常水平而嬰兒又有過敏家族史時，便屬於過敏的高危嬰兒。

此外，嬰兒最早接觸的食物致敏原通常是牛奶。有不少研究的對像是沒經篩選的嬰兒，結果找不到牛奶跟過敏的關係；然而對高危的兒童而言，牛奶卻擔當著十分重要的角色。有研究將餵牛奶配方的高危嬰兒跟完全餵母乳的比較，同時亦以牛奶配方和低敏配方相比，結果發現餵牛奶配方的嬰兒比餵母乳或低敏配方的較容易患食物過敏、濕疹或哮喘。

參考資料: <<了解過敏症>>

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的過敏病科醫生查詢，而不應單倚賴以上提供的資料。

鼻敏感治療

首要任務是避免接觸致敏原。然而，有部份的致敏原是可以避免的，如飼養動物時帶來的動物毛屑和睡房內的塵蟎。可是，在現實的環境下有不少患者寧願自己的鼻敏感情況持續下去，都不願意放棄家中寵物，這一點亦是可以理解的。

參考資料: www.allergy.hk

 

鼻敏感藥(鼻敏感噴劑 / 抗組織胺)

目前有效治療過敏性鼻炎藥物有鼻敏感噴劑，屬於消炎效力強和抗敏感的類固醇藥物。然而，類固醇噴劑的治療範圍集中於鼻腔內，患者可以在有需要的時候使用，副作用包括比較容易流鼻血。

第二類鼻敏感藥是抗組織胺。由於人體內的免疫細胞會釋放組織胺免疫因子，令患者感到痕癢、血管膨脹、血管滲水等，抗組織胺藥物可以減少痕癢、打噴嚏和流鼻水的徵狀。

脫敏治療

若需要較長期性的根治過敏性鼻炎，可考慮使用脫敏治療。

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的過敏病科醫生查詢，而不應單倚賴以上提供的資料。

Tips of Traveling with Allergies and Asthma

Reference information: www.aaaai.org

By car
Common allergens such as mites and molds lurk in carpeting, upholstery and ventilation systems. If you have pollen or mold allergies, and are traveling by car, close your windows and turn on the air conditioning to "do not re-circulate" mode.

Outdoor air pollution can make your symptoms worse. If traveling by car, think about driving during early morning or late evening when the air quality is often better and you can avoid heavy traffic. Don't travel in a car with someone who is smoking. If you use a nebulizer for your asthma, get a portable nebulizer. 

 
By plane
If you have food or pet allergies, you may benefit by checking airline policies before traveling. Some have "nut free" flights. Some allow pets to travel as passengers, others do not. Make sure to carry two doses of portable, injectable epinephrine, in case you have a severe allergic reaction while in flight.

If you have severe asthma or other respiratory illnesses, your physician may tell you to take supplemental oxygen. No one can be refused travel for needing supplemental oxygen; however, this has to be arranged in advance.

If you have sinusitis or an ear infection, the changes in air pressure in the plane could cause significant pain. If possible, try to delay your travel until your symptoms improve.
The air in planes is very dry. You will feel much more comfortable if you use saline nasal spray once every hour to keep the membranes in your nose moist.

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.

Traveling with Allergies and Asthma

Reference information: www.aaaai.org,

 

If you have allergies or asthma, you know that allergens travel with you wherever you go.
Whether you are planning a visit to family or have vacation plans far from home, think about where you are going, what you will be doing and how you will get there. PACK right to stay safe.

Plan ahead. If you are traveling by air, train or boat, you may need to go through security. Keep medications in their original packaging. Carry your medications with you, or a lost suitcase could become a health crisis.

Anticipate problems and hidden allergens. If you have asthma, be sure it is under control before you travel. If you have food allergies, let people at your destination know before you get there. Take precautions and always have your rescue medicines available.

Continue taking your medications on schedule. Your allergies don't take a break just because you are on vacation. In fact, traveling may mean you are exposed to different (and more) triggers than normal. If possible, talk to your allergist/immunologist, often referred to as an allergist, before traveling to decide if any short-term adjustments are needed.

Keep your allergist's phone number and other emergency contact information on-hand. Locate an allergist or medical center in the area you are visiting in case you need an urgent appointment. Call ahead to verify they accept your insurance. 

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.

不同的脫敏治療

塵蟎

因氣候潮濕的關係，香港的塵蟎致敏原較多。接受塵蟎脫敏治療一般所需時間較長，以6個月至一年不等才有明顯效果。不少臨床測驗指出，脫敏治療能有效地減少鼻敏感、眼睛敏感及哮喘等問題。

 

濕疹

至於濕疹，需視乎患者本身的病情，除了因為過敏而引致濕疹病發外，亦有其他因素如細菌感染和皮膚受到環境因素刺激等，即使解決了環境過敏亦未必完全把濕疹根治。所以，濕疹患者在決定接受脫敏治療前必須了解清楚，其濕疹跟過敏是否有很大的直接關係。

鼻敏感

鼻敏感患者在進行脫敏治療的首六個月需要持續用藥，當鼻敏感病徵開始穩定時，約在脫敏治療的6個月後便可開始減少用藥，大部份患者接受脫敏治療約一年便不需要用藥了。

哮喘

大部份哮喘患者在進行脫敏治療後便可以減少所需要的吸入性類固醇。在治療初期因要控制患者的哮喘情況才可進行治療，所以並不建議患者在這階段停用吸入性類固醇。進入維持階段後便可視乎病情逐漸減少哮喘藥物。

參考資料: <<了解過敏症>>

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的過敏病科醫生查詢，而不應單倚賴以上提供的資料。

House dust mite

Reference information: http://www.polleninfo.org

Pollen which appear at unusual times of the annual cycle:

Usually the pollen season starts in spring and ends in late summer / autumn. Some plants however, flower late in the year and release nonetheless considerable amounts of pollen.

Cedars flower in late September / early October and may cause conspicuous yellowish precipitations similar to what we know from pine and spruce in certain years during May.

Ivy pollen becomes airborne in small amounts at about the same time.

different species of the cypress family may flower throughout the year and release some pollen. In the Mediterranean, cypress is sometimes already in December in full flower.

In late autumn one can notice in some years a yellowish dust layer here and there, composed of rust summer spores of Puccinia (black rust or stem rust on wheat).

long - distance pollen transport

During winter time, sand from the Sahara desert is transported by strong winds far north to Europe. We sometimes detect at such occasions very characteristic pollen grains from Ephedra, which flowers in late winter in the Atlas mountains.

In particular in Scandinavia, birch pollen allergic patients must often face surprising hayfever attacks in early spring although no birch is yet flowering far and wide. Long distance transport can deposit lots of birch pollen of southern origin by suitable weather conditions. Ambitious forcast models are under development, combining methods of meteorology, aerobiology and remot satellite sensing.

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.

Pollen which appear at unusual times of the annual cycle

Reference information: http://www.polleninfo.org

Aerobiological particularities

Usually the pollen season starts in spring and ends in late summer / autumn. Some plants however, flower late in the year and release nonetheless considerable amounts of pollen.

Cedars flower in late September / early October and may cause conspicuous yellowish precipitations similar to what we know from pine and spruce in certain years during May.

Ivy pollen becomes airborne in small amounts at about the same time.

different species of the cypress family may flower throughout the year and release some pollen. In the Mediterranean, cypress is sometimes already in December in full flower.

In late autumn one can notice in some years a yellowish dust layer here and there, composed of rust summer spores of Puccinia (black rust or stem rust on wheat).

long - distance pollen transport

During winter time, sand from the Sahara desert is transported by strong winds far north to Europe. We sometimes detect at such occasions very characteristic pollen grains from Ephedra, which flowers in late winter in the Atlas mountains.

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.

舌下脫敏治療

為了令疫苗能更安全和方便，近年開始使用舌下脫敏治療方法。舌下治療是利用高濃度的致敏原疫苗滴在舌頭下吸收，這方法明顯比打針方便，而患者亦可在家中自行服藥，但必須每天服用。患者只要將疫苗滴在舌底，待兩至三分鐘後把它吐出或嚥下。然而舌下治療是較為方便，但患者如經常忘記服藥或當病情稍為好轉時便不再服藥，會令療效減少，反觀，注射治療便沒有這個問題。還有，舌下脫敏治療平均減少病徵約45%，相比注射性脫敏治療平均功效的75%亦較為遜息。

抗IgE的藥物

另一方面， 近年有專門針對免疫球蛋白E( IgE)的抗體藥物面世。當過敏患者注射後，抗體便會中和患者體內的IgE，使其無法造成急性過敏反應。此治療可對付不受吸入性類固醇控制的嚴重性哮喘患者，不過在費用方面非常昂貴，而患者亦需要每兩至四星期注射一次。這藥物的療效不像脫敏治療般有持續性，停止治療後效果便會消失。

除此之外，有研究指出抗IgE藥物可用以加快傳統的脫敏治療功效，做法是在脫敏治療開始時先注射抗IgE，減低患者的過敏程度，再以快速方法進行脫敏治療，便可在數日內達致脫敏效果。曾經有研究員嘗試使用抗IgE醫治嚴重的食物過敏病人，儘管有部份患者的病情得到改善，亦有小部份患者在注射後完全沒有反應。因成效參差，暫時都不建議使用此方法治療食物過敏。

食物過敏的脫敏疫苗

針對食物過敏的疫苗，其實早在十五年前，花生脫敏疫苗已進行臨床測試，但因副作用高而沒有成功地受接納。現時，研究員利用生物科技以改良花生脫敏疫苗，希望可減少不良反應。

總括而言，脫敏治療是針對過敏症的疫苗。此療法可有效降低，甚至消除患者的過敏，不單能幫助患者減少徵狀，還可減低患者用藥的需要和預防新的過敏症和哮喘的發展。而一般在完成三至五年的療程後，效果可長時間或甚至永久持續。在不斷研製新疫苗下，希望可以進一步治療食物和其他過敏。

參考資料: 《了解過敏症》

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的過敏病科醫生查詢，而不應單倚賴以上提供的資料。

What is pollen?

Pollen is the male gametophyte of higher plants, necessary for pollination and insemination of the female flower to induce seed production. To some extent, is is comparable to the sperma of animals, although this comparison matches only the functionality.

How is a pollen grain constructed?

The size of a pollen grain (which consists of at least two cells) is usually around 20-30 thousandth millimetres microns). This is about one third of the width of a human hair. Therefore you can hardly see a single pollen grain with the unarmed eye.

On its surface, there are lots of different, very specific proteins. They act as an identification card to exchange information with the female part of the plant. As these proteins are instantly water soluble, they are also able to penetrate the mucous membranes and cause specific reactions from the immuno system.

why is pollen in the air?

Most plant species are insect-pollinated, but a number of plants deliver their pollen to the wind.

Wind pollinated plants need a much higher pollen production to ensure pollination. Preferably these pollen, which become airborne, are the ones which cause allergies. However, not all the pollen types we can find in considerable amounts in the air do cause allergies, as for instance pine or fir pollen, or pollen of the stinging nettle, which are the most abundant airborne pollen in many regions.

The main allergenic pollen are produced by

·  grasses

·  trees of the birch tribe (which are alder, hazel, hornbeam, beech, oak and sweet chestnut

·  wind pollinated composites (mugwort, ragweed)

·  olive tree

·  wall pellitory, and

·  trees of the cypress and related families

Reference information: http://www.polleninfo.org

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.

過敏反應怎樣發生？

參考資料:《了解過敏症》

抗體引起的過敏反應
人體的免疫系統會製造一種名為免疫球蛋白E（或者IgE）的抗體，專門針對致敏原。當免疫系統產生抗體後便會經過血液進入體內各系統，如皮膚、氣管、腸胃 等。這些部位含有肥大細胞，尤以皮下最多，而肥大細胞表面則有IgE認受體，於血液內的IgE結合。當致敏原接觸到肥大細胞表面的IgE抗體時，便觸發肥 大細胞的活躍性。

活躍後的肥大細胞會釋放一些發炎因子(如組織胺、白三稀素等)，令病人產生過敏反應，如血管滲水、血管膨脹、痕癢、氣管收窄等等。此反應 可以在短時間如數分鐘至一小時內產生。鼻敏感、哮喘、蕁麻疹、風疹、急性食物過敏、藥物過敏，昆蟲過敏等都是由第一類過敏反應引起。
細胞引起的過敏反應
免疫系統的T細胞對某些致敏原產生起敏作用，當T細胞再次接觸此類致敏原時，就會釋放一些因子，引起發炎反應。延遲性過敏反應通常會在接觸後24至48小時內發生。延遲性過敏反應可以造成皮膚濕疹、接觸性皮膚敏感或食物造成的腸胃敏感等。

過敏測試
每種過敏症乃不同的免疫機制所引起，當你決定接受過敏測試時，要視乎哪一類的免疫反應來決定使用哪一種的過敏反應測試。

過敏藥
服用過敏藥亦一樣，不同的過敏症機制要利用不同的治療藥物，這一點是非常重要的。若不小心便會造成診斷或治療上的失誤。

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的過敏病科醫生查詢，而不應單倚賴以上提供的資料。

Reduce exposure to pollen, allergic to pollen

Followings are the ways to reduce the expusres to pollen:

1.No alcohol

Alcohol widens the blood vessels - also in the mucosa, which becomes thus more permeable and will lead to more intense allergic reactions. Some drugs show similar effect.

2.Wear sunglasses (and a hat)

Sunglassses prevent to some extent your eyes from pollen contact and protect them from sun radiation which irritates the highly sensitive mucous membranes of allergy affected eyes. A hat with wide brim may have an additional effect.

3.Filters

Filter masks make you look like a surgeon or an over-cautious patient, but they are effective    indeed. Pollen filters for cars are meanwhile already standard but must be maintaind (replaced) in order to guarantee good function.

4.    Rinse your nose with salty water
Blood-isotonic salt water rinses do not only clean your nose from dust, but remove the allergenic molecules from the mucosa, as they are all instant water soluble. A suitable solution is 2-3 spoonful of salt resolved in one litre of lukewarm water.

      So, most of the time it is not possible to fully escape the pollen and sometimes the hints presented above are still not good enough. There are some other things that can be done against allergies:

• There are some useful drugs, but most of them you have to take a certain amount of time before you come in contact with the allergen.
• Immunotherapy (Hyposensitization) is a technique used for getting rid of very severe allergies.
  

Reference information: http://www.polleninfo.org

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.

     

How to minimize pollen contact ?

Reference information: http://www.polleninfo.org/

There are several things that can be done against pollen allergies. The first and most effective is (as with any allergy) to avoid or minimize the contact with the allergen (in this case pollen). You may think this is impossible, but we have some help for you:

• Information about where to travel to to get relief. It is certainly a good idea to have a look at these pages before planning your vacation
• If you can't escape: Here are some hints for how to minimize pollen contact during the season. It's not that difficult.

Stay indoors

In particular on warm, sunny days with moderate wind the pollen loads can reach extremely high value. It is therefore wise to remain indoors with windows closed.

Use the filter effect of the leaves of deciduous forests

Forests are almost perfect filter machines. Once you are inside, the pollen concentration of the air is markedly reduced.

No physical exercises outdoors during the pollen season!

The more air you breathe, the more pollen you inhale with. It may be better to do physical exercises in a gym hall. However, some long distance runners reported a complete disappearance of symptoms after having run some longer distance.

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.

常見致敏原：花生

因花生過敏的情況十分常見，且漸漸引起市民關注。有研究指出，患有花生過敏的人數在英國及美國等國家正迅速增加。就此問題，世界衛生組織曾建議高危兒童（即有家族過敏史的兒童）應避免於三歲前進食花生；但亦有另一研究顯示，若能及早接觸花生，有可能減低兒童將來對花生的過敏機會。然而，泰國及中國等亞洲地區出現花生過敏的問題並不常見，原因有可能是傳統上這些地區的兒童很早便接觸花生。

研究方法：    利用以下兩種不同的烹調花生方法餵食老鼠，及觀察老鼠對花生會否產生過敏。

從以上的結論推斷，英國及美國等兒童的花生過敏有可能是因他們經常進食以高溫烘焗的花生，相反中國人的傳統以水煮花生，兒童過敏的現象並不普遍。

由於花生屬於豆類而非果仁類，對花生過敏者較大機會對其他豆類有過敏反應，如大豆、扁豆等；然而，在食物的生產過程中花生和果仁常屬同一條生產線，因此在處理時亦有機會把花生成分混入果仁中，令患者在進食果仁時產生過敏反應。

除此之外，酒樓點心及食物醬汁也有可能在烹調時加入花生醬，如春卷、蛋糕、餅乾、朱古力糖等。患者在出外用膳時，最好選擇沒有汁料的食物及看清楚所含成份，至於多芡汁及釀製的食物就可免則免。然而，烹調時所用的花生油一般是安全的，因製造時利用高溫把花生榨油，花生的蛋白質減少之同時亦減低過敏的機會，但要注意咱家製的花生油效果不同，不單增加花生油內的致敏原，危險性亦相對地增加。

參考資料:《了解過敏症》

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的過敏病科醫生查詢，而不應單倚賴以上提供的資料。

哮喘成因逐個數

亞士匹靈過敏性哮喘

白三烯素(Leukotriene)是導致哮喘的重要因素。過敏性發炎時白血球細胞會釋放出白三烯素，導致氣管肌肉收窄和嗜酸性細胞入侵氣管而引發哮喘。患有亞士匹靈過敏性哮喘的病人，他們的氣管黏膜會製造較多白三烯素，在沒有過敏反應的情況下亦如此。這疾病一般都在成年開始，與遺傳基因有關，不過需要通過後天誘發如病毒感染才會形成哮喘。這類病人通常亦患有鼻炎、慢性鼻竇炎和鼻息肉。若患者服用亞士匹靈或其它同類藥物，會引發嚴重過敏反應，令到哮喘病情惡化。目前有假說認為，亞士匹靈是通過抑制環氧化，減少具有支氣管擴張功能的前列腺素E的合成，通過一種脂氧合途徑增加白三烯素，導致患者有嚴重的哮喘病發，甚至致命。他哮喘病人服用亞士匹靈後不會有同樣反應。

職業性哮喘

有部份患者對某些工業原料有過敏反應，如油漆、塑膠工業內的化工原料等，它們含有可引起哮喘的異氰酸甲苯　(Toluene Diisocyanate)，當工人長時間吸入這些原料時會引致哮喘。其他職業若需要處理或接觸動物、某些有機產品等亦有可能引發哮喘病。

病毒感染的哮喘

過半數有哮喘的兒童都屬於過敏性哮喘，而其他引起哮喘的成因是病毒感染。有研究發現，如兩歲以下的兒童染上某種病毒感染，將來有哮喘的機會比起一般兒童高出10至100 倍。不過由病毒感染引發的哮喘通常不會持續到成年，大部份兒童在6歲後都有可能不會再發病。

主要病毒：

·             呼吸道融合病毒（Respiratory Syncytial Virus簡稱RSV）

·             鼻病毒（Rhinovirus）

參考資料:  《了解過敏症》

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的過敏病科醫生查詢，而不應單倚賴以上提供的資料。