引發哮喘的致敏原

什麼原因引發哮喘亦是一個重要的診斷元素。診斷前過敏病科醫生會先肯定或排除過敏性哮喘的可能性。在進行一系列環境致敏原的皮膚測試，便可以知道患者是否因過敏而造成哮喘。然而，亦需要先了解患者的家居情況及工作環境，因二手煙、寵物等有機會引發此問題。

慢性鼻竇炎和胃酸倒流

慢性鼻竇炎是可以誘發或加劇哮喘的問題。如鼻竇炎的症狀持續八至十二週以上，包括長期鼻塞、失去嗅覺、分泌呈黃或綠色物時，便需考慮是否患上慢性鼻竇炎。進行電腦掃描亦可看清楚病人的鼻竇情況。如不好好治療慢性鼻竇炎，哮喘的情況將難以改善。

胃酸倒流問題亦不容忽視。由於食道與氣管屬同一自主神經線操控，氣管受到胃液倒流的刺激，可導致反射性氣管收縮。胃酸倒流特別容易發生在體胖、不定時飲食習慣、吸煙或飲大量咖啡因的人士身上。若胃酸倒流治癒後，哮喘問題亦會比較容易受到控制。

亞硫酸（Metabisulphite）

成年哮喘患者當中有約5%人士對亞硫酸敏感。亞硫酸是一種食物潻加劑，具抗氧化功效。紅酒、啤酒、乾果等等均含有亞硫酸成份。當亞硫酸遇到胃酸時會造成化學反應，釋放二氧化硫（Sulphur Dioxide）。它會刺激腸胃神經系統，形成反射性氣管收縮的問題，嚴重時甚至會對生命構成危險。因此診斷和教導患者如何避免進食含有亞硫酸的食物是十分重要。

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。

怎樣診斷哮喘

要診斷患者是否患有哮喘，必須先了解他的身體狀況，從而為他定下詳細病歷。若患者有持續性咳嗽、胸口有壓迫感、喘鳴，特別是運動不久後便有氣喘時，有可能他已經患有哮喘問題。如他同時是鼻敏感或濕疹病人，患有過敏性哮喘的機會更大。

肺量檢查 (Spirometry)

哮喘是由於氣管收窄造成。所以，通過肺功能檢查﹝即量度吸氣及呼氣分量﹞便可確診。肺量檢查是最規範的肺功能檢查方法，做法是：吸一口氣，然後用力快速吐出，儀器便可量度用力吐氣時的肺活量、第一秒吐氣量和中段吐氣流速。患者在哮喘發作時的肺功能減低，所以第一秒吐氣量和中段吐氣流速同時降低。

呼吸道激發測驗 (Provocation test)
呼吸道刺激藥物如組織胺（Histamine）、甲基膽鹼（Methacholine）等會刺激哮喘氣管短暫收窄，以便觀察氣管收窄的情況。患者先吸入由低至高不同濃度的藥物，測量吸藥前和每次吸藥後第一秒吐氣量，計算其一秒吐氣量降低20% 時所需刺激藥物的濃度或劑量。若所需刺激藥物的濃度或劑量越低，便表示呼吸道過敏反應或發炎反應越嚴重。對於平時沒有氣管收窄和氣喘的患者來說，這測驗可有效診斷哮喘。

參考資料：www.allergy.hk

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。

如何診斷鼻敏感？

1當你有打噴嚏，鼻子癢及鼻塞的症狀時，亦不等於患有過敏性鼻炎，最重要的是找出導致這些徵狀的原因。
當過敏病科醫生為病人檢查時，通常會發現病人的鼻膜會因血管滲水而腫脹和蒼白，鼻膜表面更不平滑;另外，鼻敏感的分泌是無色，質地較稀（如鼻水）的，而由感染引起的鼻涕則較濃。
診斷有法
診斷鼻敏感有二大方法：
嗜酸性粒細胞：
2在患者的鼻膜內取出小量細胞，並在顯微鏡下觀察，若發現有敏感性發炎細胞“嗜酸性粒細胞“時，即表示患上過敏性鼻炎。
敏感測試：
皮膚測試是一種檢查患者對某些致敏原的過敏反應方法，從而避免/減低接觸致敏原的風險。

參考資料：www.allergy.hk

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。

花生過敏

十多年前，英國政府曾建議過敏高危的嬰兒，三歲前應避免進食花生及其他果仁食物。但是在十多年後，英國兒童對花生過敏的問題不減反增，最近有研究發現，在其他國家尤其是東南亞和以色列的幼兒，小時候便有吃花生的習慣，他們對花生過敏的比率並沒有上升的趨勢。
據一項重要的以色列研究報告指出，以色列兒童早期已經常食花生，不過他們對花生過敏的發病率只有0.3％，反觀英國在有措施的呼籲下，花生過敏發病率亦有2％，導致此情況的有可能因素是：

1。食花生的種類
研究發現，用高熱方法烹調花生，如花生醬是較容易產生過敏問題。

2。經環境所接觸

在正常情況下，食物經消化系統會令免疫系統產生忍耐反應;相反經環境而接觸，即皮膚，黏膜接觸到的花生，較容易造成過敏反應。例如，西方家庭愛吃花生醬，而花生醬的黏性很高，很大機會殘留在四周的環境如刀，叉，碟，桌子或椅子等。三歲下的幼兒雖然不吃花生，但有可能在家居裡經皮膚或黏膜接觸花生而產生過敏。
英國在這十多年間，就是因為這一個建議，使幼兒不吃花生，可惜在環境中依然可以接觸花生，令他們對花生過敏的機會提升，儘管這個建議已被取消，但暫時未有建議幼兒該在什麼年齡可吃花生。若父母不想高危的嬰兒冒險，便應在家居內完全戒掉花生，使嬰兒在環境中沒有機會接觸，否則便不要戒食，更應酌量進食。

參考資料：<<了解過敏症>>, www.allergy.hk

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。

Feel Better. Live Better.

Healthy Tips

• If you have red, bumpy, scaly, itchy or swollen skin, you may have a skin allergy.
• Hives (or urticaria) are red, itchy, raised areas of the skin that can range in size and appear anywhere on your body. Angioedema is a swelling of the deeper layers of the skin that often occurs with hives.

• When certain substances come into contact with your skin, they may cause a rash called contact dermatitis.
• The red, scaly, itchy rash often affecting the face, elbows and knees is called atopic dermatitis or eczema.
• If you have eczema, avoid scratching or rubbing your rash to prevent an infection.
• An allergist can help figure out which allergic skin condition you have and take steps to treat it.

An allergist/immunologist, often referred to as an allergist, is a pediatrician or internist with at least two additional years of specialized training in the diagnosis and treatment of problems such as allergies, asthma, autoimmune diseases and the evaluation and treatment of patients with recurrent infections, such as immunodeficiency diseases.

The right care can make the difference between suffering with an allergic disease and feeling better. By visiting the office of an allergist, you can expect an accurate diagnosis, a treatment plan that works and educational information to help you manage your disease.

Reference information: www.aaaai.org, www.allergy.hk

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.

Contact Dermatitis

When certain substances come into contact with your skin, they may cause a rash called contact dermatitis. Irritant contact dermatitis is often more painful than itchy, and is caused by a substance damaging the part of your skin it comes into contact with. The longer your skin is in contact with the substance, or the stronger the substance is, the more severe your reaction will be. These reactions appear most often on the hands and are frequently work-related.

Allergic contact dermatitis is best known by the itchy, red, blistered reaction experienced after you touch poison ivy. This allergic reaction is caused by a chemical in the plant called urushiol. You can have a reaction from touching other items the plant has come into contact with. However, once your skin has been washed, you cannot get another reaction from touching the rash or blisters. Allergic contact dermatitis reactions can happen 24 to 48 hours after contact. Once a reaction starts, it takes 14 to 28 days to go away, even with treatment.

Nickel, perfumes, dyes, rubber (latex) products and cosmetics also frequently cause allergic contact dermatitis. Some ingredients in medications applied to the skin can cause a reaction, most commonly neomycin, an ingredient in antibiotic creams. For irritant contact dermatitis, you should avoid the substance causing the reaction. You should also avoid spilling chemicals on your skin. Gloves can sometimes be helpful. Since these reactions are non-allergic, avoiding the substance will relieve your symptoms and prevent lasting damage to your skin.

Reference information: www.aaaai.org, www.allergy.hk

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.

Allergic Skin Conditions

If you have red, bumpy, scaly, itchy or swollen skin, is it because of a skin allergy?

There are several types of allergic skin conditions. They are often itchy and red and may appear scaly, bumpy or swollen. An allergist/immunologist, often referred to as an allergist, is the most qualified physician to treat allergic diseases. An allergist can determine which condition you have and develop a treatment plan to help you feel better.

While skin allergies are unpleasant and troublesome, there are things you can do to treat them.

Hives and Angioedema

Hives (or urticaria) are red, itchy, raised areas of the skin that can range in size and appear anywhere on your body. Most common are acute cases, where food or drug allergies are triggers. These hives usually go away within a few days. In cases of chronic hives, people may suffer for months to years.

Angioedema is a swelling of the deeper layers of the skin that sometimes occurs with hives. Angioedema is usually not red or itchy. The areas often involved are the eyelids, lips, tongue, hands and feet.

Food or drug reactions are a common cause of acute hives and/or angioedema. Viral or bacterial infection can also trigger hives in both adults and children. Physical urticaria are hives resulting from a non-allergic source: rubbing of the skin, cold, heat, physical exertion or exercise, pressure and direct exposure to sunlight.

If the cause of your hives can be identified, you should avoid that trigger. With acute hives, some drugs or foods may take days to leave the body, so your allergist may prescribe antihistamines to relieve your symptoms until that happens.

Reference information: www.aaaai.org, http://www.allergy.hk/

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.

引致鼻敏感的三大可能

鼻敏感可歸納以下三個成因：

1。過敏性鼻炎
2。血管舒縮性鼻炎
3。藥物
環境與過敏性鼻炎的關係
病人對環境事物敏感所引起。當鼻敏感患者吸入以下的致敏原時導致鼻膜腫脹，搔癢，打噴嚏和流鼻水等過敏性鼻炎反應。病人更會因鼻水倒流令喉嚨不適，咳嗽及有痰等問題相繼出現。
對塵蟎過敏者：
香港是常見的塵蟎過敏地區，一般以家俬，梳化，枕頭，坐墊，地毯及窗簾等積聚塵蟎。若是過敏性鼻炎的病患者，在接觸塵蟎後20分鐘內便會出現過敏反應。
塵蟎過敏病人的常見現象
*開啟冷氣時冷風把塵蟎吹起，患者會隨著冷風吹到時打噴嚏;
*進入有地毯的房間，飛機，車輛等時會打噴嚏;
*睡房床上有不少的致敏原，進入睡房時已開始打噴嚏，鼻塞及鼻水倒流，時常出現咳嗽，並難以入睡。

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。

鼻敏感成因？

1. 過敏性鼻炎
病人對環境事物敏感 (例如塵蟎, 花粉, 霉菌)所引起。當鼻敏感患者吸入以下的致敏原時導致鼻膜腫脹、搔癢、打噴嚏和流鼻水等過敏性鼻炎反應。病人更會因鼻水倒流令喉嚨不適、咳嗽及有痰等問題相繼出現。
香港是常見的塵蟎過敏地區，一般以傢俬、梳化、枕頭、坐墊、地毯及窗簾等積聚塵蟎。若是過敏性鼻炎的病患者，在接觸塵蟎後20分鐘內便會出現過敏反應。

2. 血管舒縮性鼻炎
大約半數的鼻敏感患者是由於血管舒縮性鼻炎引起的。這有可能是傷風感冒的嚴重感染導致，又或是長時間有過敏性鼻炎而造成的併發症。

3. 鼻敏感藥
診斷鼻敏感有2大方法：
嗜酸性粒細胞：在患者的鼻膜內取出小量細胞，並在顯微鏡下觀察，若發現有敏感性發炎細胞「嗜酸性粒細胞」時，即表示患上過敏性鼻炎。

鼻敏感測試： 皮膚測試是一種檢查患者對某些致敏原的過敏反應方法，從而避免及減低接觸致敏原的風險。

參考資料: www.allergy.hk

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。

濕疹診斷與測試

濕疹的病徵明顯，在診斷時並不困難，最重要的是找出誘發病症的根源。 濕疹症狀：皮膚癢及乾燥, 紅腫, 龜裂, 損傷（因長期搔癢）, 皮膚變厚過敏測試 - 在診斷嬰兒和一至兩歲的小童，首先要檢查他們有否食物過敏。

有研究指出，約有40－50%的三歲以下患有過敏性皮炎的小童有食物過敏的現象，但在少年和成 年病人較為罕見。 環境致敏原如塵蟎、霉菌和動物毛屑等，和接觸性致敏原如金屬、顏料、防腐劑等亦會引起過敏反應。 下一步驟是證實患者是否有細菌感染的跡象。

在患者發病時的皮膚表面抽取部份細菌培養，測試它有否抗藥性。若患者的抗生素藥物劑量不足時只能去除部分細菌， 存活下來的會為求生存利用基因轉變等方法產生抗藥性保護自己，故再使用抗生素時則需加倍注意。

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。

Healthy Tips of Food allergies

• The most common food allergens are the proteins in cow's milk, eggs, peanuts, wheat, soy, fish, shellfish and tree nuts.
• An allergist is the best qualified professional to diagnose a food allergy. Testing performed by an allergist often helps determine if foods are causing your symptoms.
• Some food allergies can be outgrown.
• The best treatment is to avoid the foods that cause your reaction.

• Read food labels carefully and ask about ingredients at restaurants or when eating food prepared by another person.

Feel Better. Live Better.

An allergist/immunologist, often referred to as an allergist, is a pediatrician or internist with at least two additional years of specialized training in the diagnosis and treatment of problems such as allergies, asthma, autoimmune diseases and the evaluation and treatment of patients with recurrent infections, such as immunodeficiency diseases.

The right care can make the difference between suffering with an allergic disease and feeling better. By visiting the office of an allergist, you can expect an accurate diagnosis, a treatment plan that works and educational information to help you manage your disease.

Reference information: www.aaaai.org, http://www.allergy.hk/

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.

Outgrowing Food Allergies

Reference information: www.aaaai.org, http://www.allergy.hk/

Most children outgrow cow's milk, egg, soy and wheat allergy, even if they have a history of a severe reaction. About 20% of children with peanut allergy will outgrow it. About 9% of children with tree nut allergy will outgrow it. Your allergist can help you learn when your child might outgrow a food allergy.

Treatment
The best way to treat food allergy is to avoid the foods that trigger your allergy. Although it has been shown that just smelling peanut butter will not cause a reaction, sometimes food allergens can be airborne, especially in steam, and can cause reactions. Boiling or simmering seafood is a particular offender.
Always ask about ingredients when eating at restaurants or when you are eating foods prepared by family or friends.

Carefully read food labels. The United States and some other countries require that eight major food allergens are to be listed in common language, for example, "milk" rather than a scientific or technical term, like "casein."

Carry and know how to use injectable epinephrine and antihistamines to treat emergency reactions. If a reaction occurs, have someone take you to the emergency room, even if symptoms subside. Afterwards, get follow-up care from an allergist.

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.

Symptoms of Allergic Reactions to Foods

Reference information: www.aaaai.org, www.allergy.hk

Symptoms of allergic reactions are generally seen on the skin (hives, itchiness, swelling of the skin). Gastrointestinal symptoms may include vomiting and diarrhea. Respiratory symptoms may accompany skin and gastrointestinal symptoms, but don't usually occur alone.

Severe Allergic Reactions

Anaphylaxis (pronounced an-a-fi-LAK-sis) is a serious allergic reaction that happens very quickly. Without immediate treatment-an injection of epinephrine (adrenalin) and expert care-anaphylaxis can be fatal. Follow-up care by an allergist/immunologist, often referred to as an allergist, is essential.

Symptoms of anaphylaxis may include difficulty breathing, dizziness or loss of consciousness. If you have any of these symptoms, particularly after eating, seek medical care immediately (call 999). Don't wait to see if your symptoms go away or get better on their own.

Diagnosis

An allergist is the best qualified professional to diagnose food allergy. Your allergist will take a thorough medical history, followed by a physical examination. You may be asked about contents of the foods, the frequency, seasonality, severity and nature of your symptoms and the amount of time between eating a food and any reaction.

Allergy skin tests may determine which foods, if any, trigger your allergic symptoms. In skin testing, a small amount of extract made from the food is placed on the back or arm. If a raised bump or small hive develops within 20 minutes, it indicates a possible allergy. If it does not develop, the test is negative. It is uncommon for someone with a negative skin test to have an IgE-mediated food allergy.

In certain cases, such as in patients with severe eczema, an allergy skin test cannot be done. Your physician may recommend a blood test. False positive results may occur with both skin and blood testing. Food challenges are often required to confirm the diagnosis. Food challenges are done by consuming the food in a medical setting to determine if that food causes a reaction.

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.

Tips to Remember: Food Allergy

If you have a food allergy, your immune system overreacts to a food. This is caused by an antibody called IgE (Immunoglobulin E), which is found in people with allergies. Food allergy is more likely to develop in someone who has family members with allergies. Symptoms may occur after you consume even a tiny amount of the food.

Most allergens can cause reactions even after they are cooked or have undergone digestion in the intestines. There are some exceptions. For example, some allergens (usually fruits and vegetables) cause allergic reactions only if eaten in their raw form. Symptoms are usually limited to the mouth and throat.

The most common food allergens are the proteins in cow's milk, eggs, peanuts, wheat, soy, fish, shellfish and tree nuts.

In some food groups, especially tree nuts and seafood, an allergy to one member of a food family may result in the person being allergic to other members of the same group. This is known as cross-reactivity.

Cross-reactivity is not as common with foods from animal groups. For example, people allergic to cow's milk can usually eat beef, and patients allergic to eggs can usually eat chicken.

With shellfish, crustaceans (shrimp, crab and lobster) are most likely to cause an allergic reaction. Molluscan shellfish (clams, oysters, scallops, mussels, abalone, etc.) can cause allergic reactions, but reactions to these shellfish are less common. Occasionally, people are allergic to both types of shellfish.

Reference information: www.aaaai.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.