Does living next to a freeway cause asthma?

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In a recent article published in the Journal of Allergy and Clinical Immunology, researchers  found that children who lived in a neighborhood facing intersections with major highways or railroads were 40% to 70% more likely to develop asthma than children who lived in a neighborhood that did not face a major intersection or railroad.   Studies such as these suggesting a significant link between exposure to motor vehicle traffic and the risk of developing major chronic health problems in children such as asthma, has particular relevance for residents of Ahwatukee who believe that the proposed Loop 202 expansion around South Mountain is likely to bring their homes and children’s schools painfully close to one of the busiest truck traffic thoroughfares in the country.

ref. “The Influence of Neighborhood Environment on the Incidence of Childhood Asthma: A Propensity Score Approach”
Remarks by Juhn et al. (JACI April 2010 / Volume 125, No. 4)

House Dust Allergy

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Many people recognize allergy symptoms such as a runny or stuffy nose, itchy, watery eyes and sneezing (allergic rhinoconjunctivitis) from dust exposure related to common household chores such as vacuuming, sweeping, and dusting. House dust exposure can also trigger asthma symptoms such as wheezing, coughing, chest tightness and shortness of breath.

Why does house dust cause allergic reactions?

House dust is a mixture of many substances. Its content may vary from home to home, but the most common allergy triggers are:
·         Dust mites
·         Cockroaches
·         Fungi (Mold)
·         Animal Dander (house pets as well as rodents)
Being ” allergic” to these components of house dust means that your immune system produces antibodies called Immunoglobulin E (IgE), that react with  proteins unique to the substance.  Exposure to only small amounts of the offending allergen produces an allergic inflammatory response and allergy symptoms.

Is dust allergy a sign of a dirty house?

No. A dirty house can make a house dust allergy problem worse, however. Normal housekeeping may not be enough to get rid of house dust allergy symptoms. This is because many of the substances in dust cannot be removed by normal cleaning procedures. Vigorous cleaning methods can actually put more dust into the air making symptoms worse. Even if the house is very clean, some people are so allergic that even minimal exposures may trigger their symptoms.

Dust Mite Allergy

Dust mites are the most common cause of allergy from house dust. They belong to the family of eight-legged creatures called arachnids that also include spiders, chiggers and ticks. Dust mites are hardy creatures that live and multiply easily in warm, humid places. They prefer temperatures at or above 70 degrees Fahrenheit with a relative humidity of 75 percent to 80 percent. They die when the humidity falls below 40 percent to 50 percent. They are not usually found in dry climates.

Dust samples from homes in Arizona rarely contain significant levels of house dust mite.  These is an exception however.  Home that use evaporative coolers have humidity levels high enough to support house dust mites.  It is also possible that using a room humidifier regularly will increase humidity to levels that will encourage mite infestation.
High levels of exposure to dust mite are an important factor in the development of asthma in children. People who are allergic to dust mites react to proteins within the bodies and feces of the mites. These particles are found mostly in pillows, mattresses, carpeting and upholstered furniture. They float into the air when anyone vacuums, walks on a carpet or disturbs bedding, but settle out of the air soon after the disturbance is over.
Dust mite-allergic people who inhale these particles frequently experience allergy symptoms. There may be many as 19,000 dust mites in one gram of dust, but usually between 100 to 500 mites live in each gram. (A gram is about the weight of a paper clip.) Each mite produces about 10 to 20 waste particles per day and lives for 30 days. Egg-laying females can add 25 to 30 new mites to the population during their lifetime.

Oral immunotherapy has potential for treating egg allergic children

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Recent research presented at the 2010 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) shows promising results for parents of egg allergic children.

In this first multi-center trial that involved Duke, Johns Hopkins, Mount Sinai, National Jewish and the University of Arkansas, 55 children between the ages of 5 and 18 were randomized to receive egg white solid oral immunotherapy or a placebo. The study spanned three dosing phases: initial escalation, build-up and maintenance. This was then followed by an oral food challenge at approximately 44 weeks to determine how many of the children became desensitized to egg.

Seven subjects withdrew before the oral food challenge took place. While 21 of the 40 who received the egg white oral immunotherapy passed the oral food challenge, none of the 15 who received the placebo did.

“Some of the most exciting research in allergy today focuses on possible treatments for patients with severe food allergy. This important study on the use of oral immunotherapy for children with egg allergy provides further evidence that a real treatment for food allergy will soon be possible,” commented Robert A. Wood, MD, FAAAAI, one of the study authors.

The mean cumulative dose consumed during the oral food challenge by those children who received the egg oral immunotherapy far surpassed that consumed by the placebo group. Symptoms reported during the dosing phases were mild to moderate with no symptoms reported in nearly 12,000 of the doses consumed by the oral immunotherapy group versus only 4,014 symptom-free doses consumed by the placebo group.

In the oral immunotherapy group, there were also significant decreases in egg IgE and egg-specific basophil and mast cell responses. The immune profiles and long-term tolerance of the children involved in the trial are being monitored.

This study was presented during the 2010 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) on February 26-March 2 in New Orleans. This a reprint from an article located at AAAAI.org

Will peanut allergy soon be treatable?

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Two studies presented at the 2010 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) examine the use of oral immunotherapy in peanut allergic children and continue to add hope that a treatment may be on the horizon.

Both were completed by researchers at Duke University and the University of Arkansas for Medical Sciences. In one, peanut allergic children were randomized to receive either the peanut oral immunotherapy or a placebo. The subjects went through initial escalation, build-up and maintenance dosing. This was then followed by an oral food challenge.

Twenty-three children reached the oral food challenge, 15 had received the oral immunotherapy and eight had received the placebo. During the oral food challenge, the median cumulative dose of peanut tolerated was only 315 mg for the placebo group compared to 5,000 mg (~15 peanuts) for the oral immunotherapy group. In addition, the oral immunotherapy group saw median titrated skin tests decrease from baseline to the oral food challenge.

Median peanut IgE and IgG4 levels were also measured. IgE levels did not change from baseline to the oral food challenge in either group, while IgG4 levels increased from baseline to the oral food challenge in the treatment group.

“We are encouraged by the results of this first blinded, placebo controlled study for oral peanut immunotherapy. The differences in the treatment and placebo group are significant and help guide us to the next studies,” said A. Wesley Burks, MD, FAAAAI, one of the study authors.

In the other study, the researchers looked to identify whether subjects who received the oral immunotherapy could safely ingest peanut after stopping the treatment.

Twelve peanut allergic children who completed all phases of oral immunotherapy, along with meeting certain clinical and laboratory criteria, participated in a final oral food challenge 4 weeks after they stopped receiving the oral immunotherapy. The amount of time the children received the oral immunotherapy ranged between 32 and 61 months.

Nine of the 12 subjects passed this final oral food challenge and now have peanut in their diets.

“We are now trying to identify characteristics in those subjects who were able to stop the therapy to better understand who might be a good candidate for this treatment,” commented Burks.

Over the course of the treatment, peanut IgE levels decreased from the baseline with IgG4 levels increasing. Titrated skin prick tests also decreased from the baseline. These immunologic changes support the development of tolerance.

These studies were presented during the 2010 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) on February 26-March 2 in New Orleans. This is reprint from an article located at AAAAI.org.

The Importance of Immunotherapy

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If you suffer from allergic asthma, rhinitis, conjunctivitis or stinging insect allergies, you may benefit from immunotherapy. Allergen immunotherapy, also known as allergy shots, is a form of treatment that is aimed at decreasing sensitivity to allergens. Allergens, such as pollen, mold and animal dander, are substances that trigger allergy symptoms when an allergic person is exposed to them.

Patients who receive immunotherapy are injected with increasing amounts of an allergen over several months. Immunotherapy has been shown to prevent the development of new allergies and, in children, it can prevent the progression of allergic disease from allergic rhinitis to asthma. It can also lead to the long-lasting relief of allergy symptoms after treatment is stopped.

When can immunotherapy help?

Immunotherapy may be beneficial for people with allergic asthma, rhinitis, conjunctivitis or stinging insect allergies. It is not used to treat food allergies. The best option for people with food allergies is to strictly avoid that food.

Both children and adults can receive immunotherapy, although it is not recommended for children under five because of the difficulties younger children may have in cooperating with the immunotherapy program. When considering immunotherapy for an elderly person, medical conditions such as cardiac disease should be taken into consideration and discussed with your allergist/immunologist first.

An allergist/immunologist will base the decision to begin immunotherapy on:

  1. Length of allergy season and severity of symptoms
  2. How well medications and/or environmental controls alleviate allergy symptoms
  3. Desire to avoid long-term medication use
  4. Time (immunotherapy requires a significant time commitment)
  5. Cost (this may vary depending on region and insurance coverage)

Where should immunotherapy be given?

Immunotherapy should only be given under the supervision of a specialized physician in a facility equipped with proper staff and equipment to identify and treat adverse reactions to allergy injections. Ideally, immunotherapy should be given in the prescribing allergist/immunologist’s office, but if this is not possible, your allergist/immunologist should provide the supervising physician with comprehensive instructions about your immunotherapy treatment.

How does immunotherapy work?

Immunotherapy works like a vaccine. Your body responds to the injected amounts of a particular allergen, given in gradually increasing doses, by developing immunity or tolerance to the allergen(s). As a result, allergy symptoms decrease or minimize when a patient is exposed to that allergen in the future.

Two phases are involved in immunotherapy:

Build-up phase – This involves receiving injections with increasing amounts of the allergens about one to two times per week. The length of this phase depends upon how often the injections are received, but generally ranges from three to six months.
Maintenance phase – This begins once the effective therapeutic dose is reached. The effective maintenance dose depends on your level of allergen sensitivity and your response to the immunotherapy build-up phase. During the maintenance phase, there will be longer periods of time between immunotherapy treatments, ranging from two to four weeks. Your allergist/immunologist will decide what range is best for you.
You may notice a decrease in symptoms during the build-up phase, but it may take as long as 12 months on the maintenance dose to notice an improvement. The effectiveness of immunotherapy treatments appears to be related to how long the treatment lasts, as well as the dose of the allergen. If you have not seen improvement after a year of maintenance therapy, work with your allergist/immunologist to determine possible reasons treatment failed and to discuss other treatment options.

Failure to respond to immunotherapy may be due to several factors such as:

  1. Inadequate dose of allergen in the allergy vaccine
  2. Missing allergens not identified during the allergy evaluation
  3. High levels of allergen in the environment (i.e. inadequate environmental control)
  4. Significant exposure to non-allergic triggers (i.e. tobacco smoke)

If immunotherapy is successful, maintenance treatment is generally continued for three to five years. The decisions to stop immunotherapy should be discussed with your allergist/immunologist because some patients may experience lasting remission of their allergy symptoms, while other individuals may relapse after discontinuing immunotherapy.

Are there risks?

Adverse reactions to immunotherapy are rare but do require immediate medical attention, which is why immunotherapy should be administered in a medical facility appropriately outfitted with equipment and staff capable of identifying and treating these reactions. There are two types of adverse reactions that can occur with immunotherapy:

Local reactions – These are fairly common reactions that include redness and swelling at the injection site. This can happen immediately or several hours after the treatment.
Systemic reactions – These are much less common than local reactions. Symptoms can include increased allergy symptoms such as sneezing, nasal congestion or hives. Rarely, a serious systemic reaction, called anaphylaxis, can develop after an immunotherapy injection. In addition to the symptoms associated with a mild systemic reaction, symptoms of an anaphylactic reaction can include swelling in the throat, wheezing or tightness in the chest, nausea and dizziness.
Most serious systemic reactions develop within 30 minutes of the allergy injections and will require immediate treatment. This is why it is recommended you wait in the office for at least 30 minutes after you receive immunotherapy.

(Adapted from AAAAI Topic of the Month – January – The importance of immunotherapy)

Olive Tree (Olea europaea)

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Untitled design (22) (1)The olive tree is native to the Mediterranean, Asia, and Africa and has been cultivated for it’s fruit for thousands of years.  It is a hardy, drought and disease resistant tree, well suited for the harsh conditions of the Sonoran desert.  It is an evergreen tree which can grow to 30 ft and has an attractive gray, often gnarled and twisted trunk gaining character with age.  Some trees are hundreds of years old.  The olive tree produces a small,  inconspicuous pale, white flower which is wind pollinated and produces volumes of airborne pollen in the spring.   Olive tree pollen is one of the most potent and sensitizing of the allergenic plants of Arizona.  Because of it’s association with severe springtime allergy symptoms, the city’s of Phoenix and Tucson have banned the planting of fruiting Olive trees since the 1960s.  More