The Allergic March- Children who start with Atopic Dermatitis and go on to have Asthma and Allergic Rhinitis

Redefining who goes on the Atopic March

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

July 8, 2010 · fleickly · No Comments
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