Immunotherapy for allergic diseases (2)

 

 

So how do we treat allergies?  The most obvious answer is to avoid coming in contact with allergens.  To successfully practice allergen avoidance, we must first find out what the person is allergic to, and to confirm that these allergens are responsible for their symptoms.  A positive skin test will identify allergens that the patient responds to immunologically, but it still does not confirm that these allergens cause symptoms from day to day.   

 

A careful history will be very helpful, but sometimes, challenge studies might be needed.  Measuring the level of allergens in the patient’s living and working environment might also be useful.  For certain indoor allergens such as house dust mites and animal dander, avoidance measures can be extremely helpful.  The second line of treatment for allergies is drug treatment.   

 

Drugs such as antihistamines are used to counteract some of the symptoms of an allergic reaction.  They can be useful for mild cases but are frequently not successful in controlling more severe cases.  Steroid spray is also very useful in reducing the inflammation caused by an allergic reaction.  These treatments do not address the root of the problem, and symptoms promptly recur once the patient stops the treatments.

 

The only method to eliminate allergies is by immunotherapy.  This form of therapy aims to induce immunological tolerance to specific allergens, so that patients will no longer react to them when exposed.  Traditionally, immunotherapy (also called allergy injections or desensitization) is administered by repeated subcutaneous injections of purified allergen extracts.  

 

 This carries a risk of severe allergic reactions, and the injections must be administer under the supervision of an experienced allergist with adequate emergency support.  In experienced hands, immunotherapy is very safe, especially if standardized extracts are used.  In patients with insect sting allergy, immunotherapy is >99% effective in protecting the patients from future stings, and the effect appears to be lifelong after 3 to 5 years of continuous treatment.  The effectiveness of pollen immunotherapy has also been shown to last for at least 3 years after stopping treatment.

 

Newer forms of immunotherapy are being developed.  Sublingual immunotherapy uses a very high dose of allergen extract to be placed under the tongue for absorption.  Initial studies suggest that it might be effective for allergic rhinitis and possibly asthma.  More studies are needed to confirm its efficacy and also to determine its mechanism of action.  We are currently conducting a large clinical study, which will eventually involve 120 patients with allergic rhinitis, to evaluate sublingual immunotherapy against house dust mites.  

 

 Patients with moderate to severe allergic rhinitis will be recruited.  Skin tests to common allergens will be performed to confirm sensitization to house dust mites.  A nasal challenge study will be performed to confirm that house dust mites can indeed cause nasal symptoms.  The patients will first be given conventional drug therapy including an antihistamine and a nasal spray.   

 

Patients who do not derive satisfactory results from this treatment will be randomized to receive immunotherapy or placebo for one year.  The patients will be reevaluated every three months, and those that respond to treatment will have their nasal spray gradually withdrawn.  Patients will fill in a report of their symptoms every week.  At the end of one year, all patients on active treatment will continue for another year, and those on placebo will be switched to active treatment.  Immunological parameters in the blood and nasal washings will be evaluated at the beginning of the study and after one year.]

 

 

Reference information:  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.

Immunotherapy for allergic diseases (1)

 

 

 

Allergic diseases are some of the most common diseases in Hong Kong.  It has been estimated that up to 50% of school children suffer from symptoms of rhinitis, while about 15% of them have asthma and about 10% have eczema.  The incidence of allergic diseases is also increasing around the world, as a result of changes in our lifestyle and our environment.

 

Allergic rhinitis/conjunctivitis is a common problem that many sufferers simply ignore.  The symptoms include sneezing, itchy nose, itchy eyes, runny nose, watery eyes, congestion and post-nasal drip.  However, severe cases can be quite debilitating.  Children with allergic rhinitis have been shown to suffer from poor sleep, impaired learning, bad temper and hyperactivity.  Adults with allergic rhinitis are at risk of disorders of mood and sleep.  Severe allergic rhinitis might become complicated by sinus and middle ear infections, worsening of asthma, and might affect facial and dental development in children.

 

The cause of allergic rhinitis in any individual is dependent on his/her living and working environment.  In temperate climate, pollens are the most common causes.  However, in subtropical climates such as Hong Kong, indoor allergens such as house dust mites, mould spores, cockroaches and animal dander are the most common causes.  Exposure to allergens in the work environment is also very important.

 

Why do people develop allergies?  When we are first exposed to a foreign substance, through our skin, our respiratory tract or GI tract, our immune system will strive to recognize this substance.  In most cases, our immune system recognizes that these substances are harmless and ignores them.  This is a process called immunological tolerance.  Not only does the immune system ignore these antigens, it actually develops a response that actively suppresses any reaction to the antigens.  This active suppression can be passed on from one experimental animal to another by transferring immune cells called T cells.  In allergic individuals, this mechanism somehow failed to work for certain antigens (allergens), and they develop an immune response every time they encounter these antigens.  This immune response leads to allergic symptoms.

 

 

Reference information: 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.

Immunotherapy for allergic diseases (2)

So how do we treat allergies?  The most obvious answer is to avoid coming in contact with allergens.  To successfully practice allergen avoidance, we must first find out what the person is allergic to, and to confirm that these allergens are responsible for their symptoms.  A positive skin test will identify allergens that the patient responds to immunologically, but it still does not confirm that these allergens cause symptoms from day to day.  A careful history will be very helpful, but sometimes, challenge studies might be needed.  Measuring the level of allergens in the patient’s living and working environment might also be useful.  For certain indoor allergens such as house dust mites and animal dander, avoidance measures can be extremely helpful.  The second line of treatment for allergies is drug treatment.  Drugs such as antihistamines are used to counteract some of the symptoms of an allergic reaction.  They can be useful for mild cases but are frequently not successful in controlling more severe cases.  Steroid spray is also very useful in reducing the inflammation caused by an allergic reaction.  These treatments do not address the root of the problem, and symptoms promptly recur once the patient stops the treatments.

The only method to eliminate allergies is by immunotherapy.  This form of therapy aims to induce immunological tolerance to specific allergens, so that patients will no longer react to them when exposed.  Traditionally, immunotherapy (also called allergy injections or desensitization) is administered by repeated subcutaneous injections of purified allergen extracts.  This carries a risk of severe allergic reactions, and the injections must be administer under the supervision of an experienced allergist with adequate emergency support.  In experienced hands, immunotherapy is very safe, especially if standardized extracts are used.  In patients with insect sting allergy, immunotherapy is >99% effective in protecting the patients from future stings, and the effect appears to be lifelong after 3 to 5 years of continuous treatment.  The effectiveness of pollen immunotherapy has also been shown to last for at least 3 years after stopping treatment.

 

Newer forms of immunotherapy are being developed.  Sublingual immunotherapy uses a very high dose of allergen extract to be placed under the tongue for absorption.  Initial studies suggest that it might be effective for allergic rhinitis and possibly asthma.  More studies are needed to confirm its efficacy and also to determine its mechanism of action.  We are currently conducting a large clinical study, which will eventually involve 120 patients with allergic rhinitis, to evaluate sublingual immunotherapy against house dust mites.  Patients with moderate to severe allergic rhinitis will be recruited.  Skin tests to common allergens will be performed to confirm sensitization to house dust mites.  A nasal challenge study will be performed to confirm that house dust mites can indeed cause nasal symptoms.  The patients will first be given conventional drug therapy including an antihistamine and a nasal spray.  Patients who do not derive satisfactory results from this treatment will be randomized to receive immunotherapy or placebo for one year.  The patients will be reevaluated every three months, and those that respond to treatment will have their nasal spray gradually withdrawn.  Patients will fill in a report of their symptoms every week.  At the end of one year, all patients on active treatment will continue for another year, and those on placebo will be switched to active treatment.  Immunological parameters in the blood and nasal washings will be evaluated at the beginning of the study and after one year.]

 

 

 

Reference information: hkucc.hku.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.

Immunotherapy for allergic diseases (1)

 

 

Allergic diseases are some of the most common diseases in Hong Kong.  It has been estimated that up to 50% of school children suffer from symptoms of rhinitis, while about 15% of them have asthma and about 10% have eczema.  The incidence of allergic diseases is also increasing around the world, as a result of changes in our lifestyle and our environment.

 

Allergic rhinitis/conjunctivitis is a common problem that many sufferers simply ignore.  The symptoms include sneezing, itchy nose, itchy eyes, runny nose, watery eyes, congestion and post-nasal drip.  However, severe cases can be quite debilitating.  Children with allergic rhinitis have been shown to suffer from poor sleep, impaired learning, bad temper and hyperactivity.  Adults with allergic rhinitis are at risk of disorders of mood and sleep.  Severe allergic rhinitis might become complicated by sinus and middle ear infections, worsening of asthma, and might affect facial and dental development in children.

 

The cause of allergic rhinitis in any individual is dependent on his/her living and working environment.  In temperate climate, pollens are the most common causes.  However, in subtropical climates such as Hong Kong, indoor allergens such as house dust mites, mould spores, cockroaches and animal dander are the most common causes.  Exposure to allergens in the work environment is also very important.

 

Why do people develop allergies?  When we are first exposed to a foreign substance, through our skin, our respiratory tract or GI tract, our immune system will strive to recognize this substance.  In most cases, our immune system recognizes that these substances are harmless and ignores them.  This is a process called immunological tolerance.  Not only does the immune system ignore these antigens, it actually develops a response that actively suppresses any reaction to the antigens.  This active suppression can be passed on from one experimental animal to another by transferring immune cells called T cells.  In allergic individuals, this mechanism somehow failed to work for certain antigens (allergens), and they develop an immune response every time they encounter these antigens.  This immune response leads to allergic symptoms.

 

 

Reference information: hkucc.hku.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.

Immunotherapy treats annoying allergy problem

Forty million to 50 million Americans suffer from some sort of allergy, according to a recent report from Harvard Medical School. Most medications — nasal sprays, antihistamines and the like — only treat the symptoms, not the underlying sensitivity.

The only way to diminish allergy is through immunotherapy. Allergists typically provide injections, starting with a tiny bit of what bothers the patient and slowly ramping up to larger amounts.

Immunotherapy does not exactly provide a "cure," but it can greatly reduce annoying symptoms. For example, many people can't stand more than five minutes in a house with a cat. After immunotherapy, they frequently report they can spend the night in a feline-occupied home. That's not to say they're necessarily ready to adopt several kittens for their own abode; it just means they'll need fewer tissues and less Benadryl when Fluffy is nearby.

"Nothing works 100% on everybody," says Dr. Michael Blaiss, an allergist at the University of Tennessee Health Science Center in Memphis. He estimates that 4 in 5 people who get allergy shots reap the benefit.

Reference information: http://www.latimes.com/health/la-he-allergies-immunotherapy-20100802,0,7205621.story

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.

藥物過敏治療 Allergen Immunotherapy in Hong Kong

Allergic diseases such as allergic rhinitis (nasal allergy), allergic conjunctivitis (ocular allergy) and asthma are chronic diseases.  These diseases are caused by the immune system reacting inappropriately to normally harmless substances such as pollens, dust mites, mold spores and animal dander.  While there are drugs such as steroids and antihistamines that can effectively control the symptoms, the only option for eliminating the root cause of the problem remains allergen immunotherapy (also called desensitization, hyposensitization or allergy shots).

Allergen extracts are prepared according to the sensitivities of the individual.  The extracts are administered at regular intervals to induce a response called immune tolerance.  The tolerance response is achieved by the production of blocking antibodies and regulatory T cells.  When this happens, the patient’s sensitivity to the allergens progressively diminishes, and symptoms also decline.  Studies have shown that after three to five years of treatment, the effectiveness persists long-term even after treatment is discontinued.

Allergic rhinitis in childhood is a risk factor for the development of asthma.  A study shows that children who received allergen immunotherapy for allergic rhinitis have 2.5-fold reduced risk of developing asthma.  This effect is still evident 10 years after treatment.

Recent studies have also shown that for a subset of patients with atopic dermatitis, where environmental allergy is a major factor in their illness, immunotherapy is effective in reducing the severity of their skin disease.

Allergen immunotherapy has traditionally been administered by subcutaneous injections. Newer forms of treatment such as sublingual immunotherapy have been developed that are more convenient, and maybe suitable for selected patients

Reference information: 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.