Archive for May, 2010

Allergy Shots Part 2: What Types Of Allergies Have They Been Proven To Effectively Treat?

May 26, 2010

There have been many studies evaluating the effectiveness of allergen immunotherapy or allergy shots.   The most rigorous scientific studies are those that are placebo-controlled and double-blinded.  A placebo-controlled allergy shot study is a study where some patients receive actual allergy shots and some receive injections of saline placebo.  A double-blinded, placebo-controlled allergy shot study is a study that is placebo-controlled and neither the patient nor the physician knows who is getting the allergy shot and who is getting the saline placebo.

Double-blind, placebo-controlled clinical studies have proven that allergy shots improve the quality of life, reduce symptoms and reduce the need for medications in children and adults with the following allergic conditions:

1. Nasal and ocular allergies (Allergic Rhinitis and Allergic Conjunctivitis)

2. Allergy-related asthma

3. Bee sting allergy:  All people who have experienced life threatening reactions to bee stings should be on allergy shots to help prevent these reactions in the future.

Allergy shots have been proven to work for grass pollen allergy, tree pollen allergy, weed pollen allergy,  mold spore allergy, allergy to animals such as cats and dogs, cockroach allergy and dust mite allergy.

Other benefits of allergy shots:

1. About 1/3 of patients with allergic rhinitis (nasal allergies) eventually develop asthma.  Allergy shots can decrease the risk of developing asthma for someone who only has nasal allergies.

2. Someone with an allergy to one allergen, such as dust mite, is at an increased risk of developing an allergy to another allergen, such as tree pollen.     Allergy shots for one allergen can prevent a person from becoming allergic to other potential allergens.

3. Allergy shots can be effective for atopic dermatitis or eczema that is associated with allergy to aeroallergens such as dust mites or pollens. 

4. Some studies have shown that allergy shots might help with the oral allergy syndrome.  (see Tree Pollen Allergy and Foods: The Oral Allergy Syndrome; 4/9/10)

Allergy shots are NOT effective for food allergy and should not be used for hives or angioedema.

Note: The content of this blog is for informational purposes only and is not meant as specific medical advice for a specific person.   If you have a medical problem, please contact your doctor.

Allergy Shots Part 1: What Are They? How Do They Work?

May 25, 2010

Allergy shots, or allergen immunotherapy, is the only FDA approved treatment available to make someone less allergic to a specific allergen.  All other FDA approved therapies for allergies are directed at controlling symptoms.  Allergen immunotherapy is directed at changing the immune response.  Allergen immunotherapy administered with shots is the only FDA approved method in the United States.   There is a lot of ongoing research on administering allergen immunotherapy through droplets under the tongue (sublingual immunotherapy).  This form of immunotherapy is used in Europe.

The purpose of the immune system in general is to protect the body against microorganisms (germs) and act as scavengers within the body to remove defective, dying or abnormal cells.  The allergic arm of the immune system directs itself against otherwise harmless substances such as dust mite or tree pollen with an allergic immune response mainly mediated by the allergen antibody called IgE.    When an allergen and a specific IgE against that allergen is present in an allergic individual, the IgE binds to cells in the immune system causing the immediate release of allergic mediators such as histamine and leukotrienes.  This causes immediate symptoms and initiates a larger and more progressive allergic immune response.  Allergy shots work by changing the immune response away from an allergic immune response. 

There are many complex changes that occur within the immune system with successful allergen immunotherapy.  It is important to note that the changes are very specific and do not affect other aspects of the immune system.  The various changes are as follows:

1. Shifts the immune response toward a non allergic response to the allergen. 

2. Generates specific regulatory immune cells that induce immune tolerance, or a decrease in the immune response, toward the allergen.

3. Induces the production of non allergen antibody called IgG toward the allergen.  These antibodies can block the allergen antibody (IgE) from releasing mediators such as histamine, that are responsible for allergic symptoms. 

4. Blocks the immediate and late phase allergic response.

5. Decreases the recruitment of inflammatory cells that contain mediators to the nose, eyes and lungs. 

6. Decreases the rise in allergen antibody that occurs in allergic individuals during the allergy season. 

Many people think of allergen immunotherapy as a more natural approach to the treatment of allergies since it utilizes the allergens themselves to induce immune changes.  That might be true, but it is important to point out that allergen immunotherapy is NOT a homeopathic approach to allergies.  Homeopathy is based upon treatment using minute quantities of substances.  Allergen immunotherapy starts with minute quantities of allergen, but doses are gradually increased and it only really works when high doses called maintenance doses are administered. 

Stay tuned for more information on allergen immunotherapy. 

Note: The content of this blog is for informational purposes only and is not meant as specific medical advice for a specific person.   If you have a medical problem, please contact your doctor.

FDA Announces “Bad Ad Program”

May 13, 2010

The FDA announced yesterday a new program called the “Bad Ad Program” designed to help health care providers detect and report misleading drug advertisements.  When I read about the new program it immediately brought to mind the various antihistamine advertisements touting how a particular drug works against outdoor and indoor allergens.  The ads basically imply, without specifically saying, that one antihistamine works for all types of allergies whereas another might only work for indoor allergies and another for only outdoor allergies.  I have had many patients ask me if a particular drug that seemed to be working for pollen allergy would also work for indoor allergies such as cat or dust mite allergy. 

The bottom line is histamine is a mediator that is responsible for many of the symptoms of allergies.  If a person is allergic to an allergen and has allergen antibodies (IgE antibodies) circulating in their system directed against a particular allergen, histamine is released by cells in response to the allergen.  Antihistamine medications act against this histamine release regardless of the allergen that is causing the problem.   Antihistamines work for histamine release caused by a food allergy, medication allergy, pollen allergy, dust mite allergy or pet allergy. 

It is completely misleading for a pharmaceutical company to create an ad highlighting the fact that their antihistamine works against indoor and outdoor allergens, since all antihistamines work against indoor and outdoor allergens.  Now, you may ask, how is it that one company can include this in their ad and another can not.  Well, that is actually the FDA’s fault.  The FDA approves each medication for a specific indication.  If the drug company does efficacy studies on an antihistamine using outdoor and indoor allergens, the FDA will approve the medication for both.  If the drug company’s efficacy study for a particular antihistamine only involves pollen, the FDA approves the drug specifically as only being indicated for seasonal pollen allergies (or outdoor allergies) and not indoor allergies.  This does not mean the medication does not work for indoor allergies, and the FDA should know that.  The problem is, drug companies are only allowed to include in their ads information pertaining to the specific FDA approved indication of the medication.   

Note: The content of this blog is for informational purposes only and is not meant as specific medical advice for a specific person.   If you have a medical problem, please contact your doctor.

Air Purifiers

May 11, 2010

There are lots of different air purifiers on the market and I will often be asked by patients which air purifier is the best.  First off, it is important to make a differentiation between HEPA filtered air purifiers and the rest.  I recommend HEPA filtered air purifiers to my patients.  They work by filtering out very small particles from the air as the air passes through the filter.  The size of the unit you need depends on the size of the room.  If the window or door to a room is open, the air purifier will not be as efficient in filtering the air in the room.  

I think the best brand is IQAir.  Unfortunately, it is also the most expensive.   There are units you can purchase that contain a carbon filter in addition to a HEPA filter.  Carbon filters help remove odors and chemical pollutants from the air.

I do not recommend that you buy any air purifier that produces ozone.  Many of these types of air purifiers have electrostatic panels that you wash, instead of HEPA filters that need to be changed.   Although they often only emit small amounts of ozone, why emit ozone into your home if you don’t need to?

Note: The content of this blog is for informational purposes only and is not meant as specific medical advice for a specific person.   If you have a medical problem, please contact your doctor.

Food Allergy And Skin

May 3, 2010

There are many in the medical profession who do not think food allergy is a major cause of eczema/atopic dermatitis.  That might be true for adults, but about 37% of children with eczema have at least one food allergy.  If you look at the statistics in reverse, you find that about 90% of children with food allergy have eczema.   In general, it is worthwhile to do food allergy testing on an infant or young child with severe eczema.  If a particular food is identified,  a trial elimination diet should be pursued to determine the impact of the elimination on the condition of the skin.

Another skin condition associated with food allergy is hives.  Hives can occur suddenly in an otherwise well person.  This form of hives is called acute hives.  If hives last more than 6 weeks they are called chronic hives.

A food can be identified as the cause in about 20% of cases of acute hives.  In this setting, if food is responsible, it generally occurs within minutes to 1-2 hours consumption of the food.  A detailed history will often reveal one or more suspect foods and allergy testing should be done to verify whether or not a person is allergic to any of those foods.

When a person has chronic hives lasting more than 6 weeks, a much smaller percentage have an associated food allergy.  Only about 4% of children with chronic hives have a food allergy and about 1.4% of adults with chronic hives have a food allergy.  Whether or not it is necessary to do food allergy testing in the setting of chronic hives depends on the patient’s history.

Note: The content of this blog is for informational purposes only and is not meant as specific medical advice for a specific person.   If you have a medical problem, please contact your doctor.

Sex and Trees and Pollen

May 2, 2010

Pollen is produced by the male flowers of plants and trees.  The flowers of trees that produce pollen do not need to be particularly pretty or colorful.  In fact, as a general rule, the less attractive the flower, the more the plant relies upon wind to spread the pollen around.  Conversely, the more attractive the flower, the more likely it is that pollination is facilitated by insects that are drawn to the plant by the flower itself.

Some trees have male and female flowers on the same tree.  These are called Monoecious trees.  Examples of these trees are Alder, Beech, Birch, Cedar, Hemlock, Honey Locust, Oak, Pine, Plane and Spruce.

Others have male and female flowers on separate trees.  These are called Dioecious trees.  Examples of these trees are Ash, Box Elder, Cedar, Cottonwood, Ginkgo, Juniper, Mulberry, Poplar and Willow.

Now, if only the male flowers of trees produce pollen, aren’t female Dioecious trees hypoallergenic by definition?  The answer to that is yes.  The question that is harder to answer is whether surrounding yourself with only female Dioecious trees can help your tree pollen allergy symptoms.  The answer to that is likely yes and no.  Female Dioecious trees and Monoecious tress exist within the real world of nature and we know that  tree pollen can travel great distances with pollen found by researchers up to 2000 feet in the air and up to 25 miles off shore.  Therefore we know that people allergic to tree pollen are affected by pollen from trees planted far from their local neighborhood or back yard.  However,  it makes sense, that the pollen from local trees, especially those in someone’s back yard or on the block where they live, will contribute to the local pollen count and the more local pollen produced the higher that count.  People allergic to tree pollen are all too familiar with the problems from that tree “right outside my window”.

So, what do I suggest?   If you are in a position of deciding what type of tree is planted in your yard or on the street by your house or apartment, by all means choose a female Dioecious tree.  There are plenty of wonderful female Dioecious trees to choose from and it might help reduce the level of pollen in your immediate area.  Just don’t expect to be free of tree pollen allergy symptoms no matter how many female trees you are able to surround yourself with.  Nature will take care of making sure you are exposed to pollen regardless.