I was intrigued to see a recent article in the American Journal of Respiratory and Critical Care Medicine (Volume 183. pages 582-588, 2011) that dealt with asthma and swimming pools. The title of the article was ‘Swimming Pool Attendance, Asthma, Allergies, and Lung Function in the Avon Longitudinal Study of Parents and Children Cohort’ written by Font-Ribera and others. What follows are a number of interesting points about swimming pools and asthma that appear in the article.

Background

There is the suggestion that swimming in chlorinated swimming pools is a risk factor for developing asthma. The theory was that cleaning products had an effect on the airway which could lead to the development of asthma. Studies were references showing increased asthma in lifeguards and a higher prevalence of asthma in elite swimmers.

These observations were also thought to be due to ‘reverse causation (where the effect preceded the cause)’- swimming is recommended for those with asthma.

There have been many epidemiologic studies done in Europe regarding swimming as a risk factor for asthma, however the results are conflicting. Of note is the statement “….there is agreement on the complexity of the potential role of swimming asthma etiology and the important public health implications.

Asthma is one of the most common chronic conditions in childhood and swimming is one of the most popular sports/activities. So, a study was done to address some of these issues

The purpose of the study

To examine whether swimming at different periods during early childhood is associated with the prevalence of asthma and allergy symptoms.

How they did it

This was part of a large cohort study. In such a study a group of children are recruited and watched over time for events to occur. This was done as part of the Avon Longitudinal Study of Parents and Children (ALSPAC) and comes from the United Kingdom. More than 5,700 children were evaluated. Asthma symptoms were reported using a standardized tool (the International Study of Asthma and Allergies in Children- ISAAC). Lung function was measured and a methacholine challenge was performed (measures airway hyper-reactivity)

Swimming frequency was asked at various times of the child’s life. There were a variety of possible confounding variables looked at as well; sex, birth weight, number of siblings, atopy, maternal education, maternal and paternal social class, maternal age at delivery, maternal asthma, allergy and hay fever, contact with pets, hours of TV watching, exposure to environmental smoke, and body mass.

What they found

The total number of children in the study was 5,738. Only 12% of the mothers had asthma. Positive allergy skin tests were seen in 21.4%. Asthma was present in 20%.

The crude and an adjusted model looked at using a variety of variables and both gave similar results. When all the confounders were accounted for, swimming was not associated with ever having asthma. Interestingly, swimming was associated with a lower prevalence of currently having asthma and currently using asthma medication at age 7 years. There was also no significant association seen between swimming and current wheezing, eczema, nasal symptoms, or eye symptoms at age 7 or at age 10 years.

The data was looked at from the perspective of the effect of swimming when there were previous respiratory tract symptoms at different ages. The protective effect of swimming was only seen among children who wheezed prior to age 3.5 years.

Of note, there was no significant association between swimming and bronchial hyper-reactivity.

Swimming also did not increase the risk of any respiratory tract symptom in children who were atopic.

Conclusions

This large prospective birth cohort study did not find that swimming increased the risk for asthma, atopy, or any respiratory/allergic symptom in British children. Swimming was associated with better lung function and decrease asthma prevalence in children who had previous respiratory tract symptoms.

The authors do point out a few problems with the study. The questionnaire asked about swimming and not swimming pool attendance. It was assumed that since this was done in the United Kingdom and the weather being what it is, the assumption was that the affirmative answer did refer to pools. Chlorine is the most commonly used disinfectant. However, no information was collected regarding the amount of chlorine exposure.

Reviewers Note

This was a large study and a prospective study that looked into a very practical question. The more children the study, the stronger the conclusions.
Swimming did not make things worse and in fact lung function was better and the risk of asthma symptoms and medication used was lower in those children who were known to have wheezing when they were younger.

Swimming is a good thing!

FEL

Does improvement management of atopic dermatitis influence the appearance of respiratory allergic diseases? A follow-up study. Clinical and Molecular Allergy 2010 8:8 Published June 30, 2010. Authors- G Ricci, A Patrizi, A Giannetti, A Dondi, B Bendandi, and M Masi.

Background and purpose of the study

Atopic dermatitis (AD) is one of the most common skin conditions that affect children. AD is characterized by dry, itchy, rough, and flaky skin. Between 70-80% of children who have AD have an elevation of the antibody associated with allergy- IgE and antibodies to foods/inhalants.  Many children outgrow this condition and in some it persists into their adulthood. In some children AD is the first step along the allergic march; going on to have asthma and allergic rhinitis. Depending upon who you ask or quote, 25-80% go on to have asthma. That is a huge range. The authors of this study published a 10 year follow-up study in 2006 looking at this issue. They showed that the AD disappeared in 60%, 34% developed asthma, and 58% developed nasal allergy. So some, not all finish the allergic march with a better chance of having nasal allergy and about a 1/3 chance of developing asthma. This begs the question as to whether or not anything can be done about it.

This current study looked at the effect of clinical management on the subsequent development of other allergic conditions and they used more standardized and contemporary measures of the conditions in asking what are the risk factors in children who have AD that may predict the development of other allergic conditions.

This is a study from Italy. It was a retrospective analysis; children who had AD between 9-16 months of age were contacted for participation. They had to have been seen in the clinic between 1993-2002.

Methodology

The assessment included;

1. Diagnosis of AD based on Hanifin and Rajka criteria (well established for this condition)

2. AD was evaluated by the SCORAD index at the first visit ( a measure of disease severity)

The clinical management program involved;

1. Environmental management- house dust mite avoidance, high-filtration vacuum cleaning,

2. Skin care- emollients, topical corticosteroids, calcineurin inhibitors, oral steroids, immunosuppressants, biologicals, antibiotics, antihistamines, and leukotriene inhibitors

Allergy Assessment;

1. Skin prick tests (SPT), total IgE  and specific IgE tests- milk, egg, soybean, wheat, peanut, nut, codfish, apple, grass pollen, house dust mite, cat dander, and dog dander. A positive was any value >0.35 for the blood test and a wheal response on the SPT.

Telephone interviews

Results

Telephone interviews were conducted with the families of 176 children. Their ages ranged from 6-12 years. The average age at the time of the first evaluation was about 1 year.

One hundred of the 176 (57%) showed a sensitization by SPT to at least one of the foods/inhalants.

One hundred and three of the 176 (58.5%) had an elevation at least one specific IgE blood test.

After an average of 7.5 years 84 (48%) still had AD- it disappeared in 52%. In the group of children who still had AD, 44% had a single site involved (mostly on a limb) and 18% had multiple locations of AD.

When AD disappeared on the average, the child was 3.25 years old.

In this group of children, respiratory allergy conditions appeared in 66/176 (37.5%).The specific respiratory ailments were; 36 (20.5%) developed only nasal allergy, 18 (10%) developed only asthma, and 12 (7%) developed both.

The nasal allergy appeared at 4.8 years of age. The mean age of appearance of asthma was 3.33 years. Asthma tended to precede the development of the nasal allergy.

A mathematical model, logistic regression, was used to predict the occurrence of asthma. A child who developed nasal allergy or was positive to at least one inhalant (serum specific IgE >0.35) at the time of the first evaluation had a greater risk to develop asthma (odds ratio was 4.219).

Conclusions (authors’)

The results of this study were compared to their earlier study in which disease-specific management was not evaluated. In the current study, the use of integrated management of AD did not seem to influence the natural course of AD. However, the early diagnosis and improved management at specialty centers decreased the percentage of children who went on to develop respiratory allergic disease. The presence of early allergic sensitization at age 1 year may predict the development of respiratory allergy.

                                Percentage of Children with Allergic Conditions – Comparing the two studies

                                1981-1989 study                                                                               1993-2002 study

Resolved AD             60.5%                                                                                                  52%^*

Asthma                     34.1%                                                                                                  17%

Nasal Allergy            57.6%                                                                                                  27%

* not significantly different

In the present study at age 8 years (mean age of the children) 15% already had asthma. In the previous study, 29% had asthma by age 8 years. The management program accounted for a reduction in the appearance of asthma in this group. Similarly, the percentage with nasal allergy fell from about 35% to 17%. This could be due to better management of the AD.

This study used quantitative evaluations with determinations of specific IgE sensitivities and the use of improved clinical tools for assessing AD (SCORAD index, environmental prevention, integrated management) that helped with the early diagnosis, appropriate therapy, and monitoring of children with AD. This may have been  helpful in decreasing the numbers who go on to have respiratory allergy.

Reviewer’s comments

I was surprised at the wide range of children who go on from Atopic Dermatitis to Asthma to Allergic Rhinitis. More definitive epidemiologic work is needed to have a more precise estimate. I hear all too often from other allergists that it is an absolute fact; if the child has AD they will have…..This group of investigators had previously  looked at this evolution to other allergic conditions in the 1980s. This earlier study served as a nice comparison group for the current study.

Back in the80′s the tools and criteria differed. The current study tries to standardize the diagnosis of the allergic conditions. The entire group of children were evaluated with the same tools for AD severity and for respiratory allergy.

This study looks at the impact of early evaluation and the impact of management programs on the occurrence of detouring children who may have been on that allergic march. The first detour was asthma and the second change of course was allergic rhinitis.

Evaluation and management seems to re-direct some of these children away from respiratory allergy. it is not known if these conditions appear later in life. That will be a paper for review perhaps 10 years from now.

 The foods that were important were eggs and milk. A specific IgE level was >2.0KU/L to milk or egg was found to be predictive of sensitization to inhalants in late infancy.

Other considerations are that this is a group of children from Italy- the genetics may differ and certainly the environment differs. Such a study needs to done on our population of children to see if the results can be replicated.

As noted by the authors, demographic information was lacking making it a bit more difficult to describe and characterize the population.

Do we need to be more aggressive with our AD children? When should all these evaluations be performed. In this study many of the children had progressed and were very severe at the time they presented to the specialty clinic. The study did not look at how long treatment should be tried before embarking on a more Allergy/Dermatology Specialty oriented evaluation.

I like the selection of allergy tests here. Nut and apple were a surprise for a first evaluation for specific IgE to food at age 1 year. We did not see shrimp or scallops as a choice here.  Also, the evaluation for the inhalants was looking at sensitization- has the child begun to make antibodies towards these items? The study used these as associations and not necessarily as cause/effect items.

I think we need to re-think about the number of children who march from AD to other allergic conditions. It never was 100% – here is it about a third of children who do this. A take home message here is to consider being more aggressive with our evaluations, monitor more frequently, and carefully in hopes of halting that march from AD to Asthma to Allergic Rininits.

FEL

During a career you hear many words of wisdom from your mentors who are with you seeing children in the office and from meetings, curbside conversations/consultations, and from the literature. The adage that allergic children get sick easier, more frequently, and have more severe illnesses has been out there for many years. There are a number of theories for this contention. Children with allergy tend to remedy their itchy nose with internal manipulation, otherwise known as nose-picking. The finger serves as the vector for direct inoculation of viral particles onto the respiratory tract. Also, a number of years ago a publication reported that allergic noses actually had more receptors for the cold virus than non-allergic noses.

The May issue of the  Journal of Allergy, Asthma, and Immunology (Volume 125 No 5.) has an article by Jaime Olenec, ‘Weekly monitoring of children with asthma for infections and illness during common cold seasons’ concluded that atopic (showing IgE antibodies) children with asthma do have more frequent and more severe asthma exacerbations due to the common cold. The bottom line for me is the impact that the specialty of allergy and the determination of sensitization to allergens can make on children with asthma. The study did not address allergen control measure effects on frequency/severity of asthma symptoms.

My review of the study-

The group who did this is excellent and has a long established research track record and publication record regarding the role of viruses and allergy in pediatric asthma.

The journal in which this was published is peer-reviewed and a top-notch allergy journal. Also of note is that the manuscript was submitted in September, 2010 and was accepted for publication four months later.

The support for the work was from the National Institutes of Health.

The purpose of the study was to look at the impact of viral infections and allergic sensitization on the loss of asthma control during the peak ‘cold’ season.

The study involved 58 children between the ages of 6-8 years who were known to have asthma. These children were followed for three years. Skin testing and specific IgE testing was performed on all. Nasal samples were collected and analyzed for human rhinovirus infection. Diary cards were kept for symptoms. Cold and asthma symptom scores were collected along with peak flow value recordings and notations of the frequency albuterol (rescue inhaler) usage.

There were 42 children who had at least one season of complete data. The average age was 6.5 years and there were 30 boys and 12 girls. In this group 50% had one or more positive skin prick test for an allergen. Of note is that 69% had one or more positive blood tests for an allergen. Additional baseline information included; daily asthma controller medications used by 88%, and oral corticosteroids were used by 57% in the past year. Fifty five percent of the mothers and 40% of the fathers had allergy.

The number of viral illnesses per season was higher in the allergen sensitized group; 47% more virus-associated illness per season. During documented viral infections (viral cultures were frequently performed), the non-atopic children commonly reported no or mild cold symptoms. In the sensitized (atopic) children symptoms tended to be more moderate or severe. Also, almost half of the viral infections in the sensitized children caused moderate or severe asthma symptoms.

The author’s conclusions were that respiratory tract illnesses (asthma symptoms) due to viruses were more severe and were more frequent in children who are atopic.

These were children with asthma who had a positive allergy test. The terms sensitized and atopy were used to describe the group. Asthma frequency and asthma severity was increased in those who have made at least one IgE antibody to something.

This was a small study which was done in only one site. Larger studies in a variety of populations need to be done to confirm these observations.

This work re-affirms my practice of being aggressive with my allergic asthmatic children when the first signs of a cold occur. I advocate stepping-up the treatment program and continuing it for up to 14 days. One of the charts shows that the average duration of cold symptoms was 8.1 +/- 5.6 days and the average duration of asthma symptoms was 7.2 +/- 7.8 days in those who had a documented rhinovirus infection. For me this fits nicely with what I advise- on the average cold symptoms may begin the day prior to asthma symptoms and at the extremes of the range, asthma symptoms may last 14 days in some children.

FEL