Does allergic rhinitis exist in infancy?

Does the baby have ‘allergies’?

How often has this question been asked? Better yet, how often are infants and young children subjected to extensive/ expensive testing and related therapies based on the idea that they are struggling with nasal allergy? This is a common concern and a common diagnosis. I am not sure it is always the correct diagnosis.

A diagnosis should lead to a treatment program. The consequences of (mis)diagnosing nasal allergy in infants may include an altered diet, removal of pets, medications (and the struggles of administering them), and even immunotherapy (a real issue in children less than 5 years of age, may even be contraindicated, and there are no studies regarding safety or efficacy of allergen immunotherapy in this age group). The medical literature has precious few published studies on this problem of infants having nasal allergy. Recently a study has appeared in the literature that takes a hard look at this problem.

So, can infants have nasal allergy (allergic rhinitis- AR) and if they can (and do) what are risk factors associated with the condition? Note that in the study the authors are calling the condition ‘Allergic Rhinitis-like’ .

In the February 2011 issue of  Allergy  (Allergy 2011; 66: 214–221) Herr and colleagues have the following article, ‘Does allergic rhinitis exist in infancy? Findings from the PARIS birth cohort. This article has a few things that excite me; allergy, allergy in young children, and epidemiology (from all the extra schooling for my Masters of Public Health). Here is my review of that article.

Purpose of the Study

The purpose of the paper was to look at the prevalence of AR-like symptoms and to study potential risk factors for atopy in a population of infants. The study was performed in Paris, France.

How they did it (Methods)

Participating children/families were part of the PARIS birth-cohort. All participants responded to a standardized questionnaire. Laboratory studies included tests for markers of allergy. The allergens that were evaluated included house dust mite (limited to the species common in Europe), pets, grass pollen, weed pollen, tree pollen, and mold spores. The foods that were tested included egg, milk, peanut, mustard, fish, wheat, soy, hazelnut, sesame seed, shrimp, beef, and kiwi.

What they found (Results)

The entire cohort numbered 4,177 children. From that number, 1,850 were analyzed for this study. The children were evaluated at 18 months of age.

AR-like symptoms occurred in 169/1850 (9%). AR-like symptoms were nasal congestion, nasal discharge, and sneezing.

There was no significant difference between the AR-like group (169) when compared to the non-AR children (1,681) for the following;

  •                 Male sex  (no sex predisposition)
  •                 Socioeconomic status (household income)
  •                 Number of siblings         
  •                 Tobacco smoke exposure
  •                 Breast feeding
  •                 Parental history of asthma or eczema
  •                 Total IgE level
  •                 Food allergen sensitization
  •                 Having only one marker of atopy

The one maker of atopy was one of the following; elevated blood eosinophil count, a total IgE > 45 U/ml (this is determined by a blood test), or sensitization to inhalant allergens only (eosinophils are cells that are associated with allergic reactions). So these factors did not sort out the group with vs. the group without AR-like symptoms. They were not risk factors.

The factors that were significantly different between the groups were;

  •                 A parent’s history of nasal allergy
  •                 Increased eosinophils in the blood (> 470/mm3)
  •                 Inhalant allergen sensitivity (any positive)
  •                 House dust mite sensitivity (Dermatophagoides pteronyssinus)
  •                 Sensitization only to inhalant allergens
  •                 Having >2 of the markers of allergy

This information was entered into a mathematical model which provided an odds-ratio for the risk factors. The factors that increased the odds-ratios were;

  •                 Mother having allergic rhinitis (OR =1.54)
  •                 Both parents having allergic rhinitis ( OR = 2.09) (Dad’s history adds a little more risk)
  •                 Elevated blood eosinophil counts (OR = 1.54)
  •                 Inhalant allergen sensitization (OR = 2.21)
  •                 Sensitization to house dust mite (D.p.) (OR = 2.91)
  •                 >2 markers of allergy      (OR  = 2.16)

(Reviewers note-an Odds-Ratio is the odds of developing the condition when the factor is present divided by the odds of that factor in those who do not have the condition. If the Odds-Ratio is 1.0 there is identity and there is no difference at all. If the OR is negative, there may be a protective effect. If the OR is significantly greater than 1.0 then there is a greater chance of having AR-like symptoms with that risk factor.)

Conclusions (Authors’)

The prevalence of AR-like symptoms was 9.1% by age 18 months in this population of French children. The significant associations for having AR-like symptoms were having both parents with nasal allergy or the child having a marker of atopic disease. Allergic rhinitis can occur as soon as the first year of life.

There is a strong genetic component- there is a twofold increased risk of AR if both parents have AR. This was not seen if the parent had asthma or eczema.

The authors concluded that the total blood IgE level was of borderline significance.

One of the major findings was the association of AR-like symptoms with sensitization to the house dust mite. There was no association found with food sensitization. Pollen, mold, or pet sensitization was not a factor (reference is made to the need for at least two seasons of exposure prior to sensitization to pollen).

The authors point out that one of the strengths of this study is the objective measure of atopy in a very large sample of children <2 years of age.

One of the limitations is the <50% participation rate by the PARIS cohort.

Reviewer’s Comments

I struggled somewhat with cohort studies, relative risks, case-controlled studies and odds-ratios and how they are used. I concluded that this was a cohort for which case-controlled analyses were used. I had to dig up my epidemiology books as I went over the tables/results. Cohort studies and case-control studies lend themselves to different epidemiologic evaluations.

As with many studies, the conclusions are relative to the population which was studied. This is from Europe, the findings may not be valid here. However, the uniqueness of the study is the use of a large population of young children. We have not seen studies of this intensity in a young pediatric population.

Also consider the condition was AR-like. AR-like included symptoms seen in nasal allergy- congestion, discharge, and sneezing. As a long time sufferer from grass pollen triggered AR, I have sneezing fits, runny nose, itchy nose, congestion, as well as the ocular symptoms of red, watery, and very itchy eyes. These respond to an antihistamine. It would have been interesting to know if antihistamines were ever used and what the response was to this standard form of treatment. That may have helped solidify the diagnosis.

As I look at the significant levels of association for risk factors and odds-ratios I see the following risk factors of value when considering nasal allergy in a child with AR-like symptoms-

  •                 The presence of nasal allergy in both parents
  •                 An elevated blood eosinophil count (if a blood draw is needed)
  •                 Evidence of sensitization to the house dust mite

Those things that this study that I found not associated (based on statistical test results)

  •                 Total IgE
  •                 Allergy tests to foods, pollens, molds, and pets at this age.

So about 10% of children at 18 months of age who have nasal allergy-like symptoms. If allergy is at work in these children then you would have both parents with nasal allergy and/or evidence of sensitization to a house dust mite and/or an elevation of their blood eosinophil count.

Perhaps information like this with help sort out which young children may have allergy accounting for their nasal symptoms and it may help in limiting items for allergy testing.

The other issue comes from forward thinking the problem. Infants usually sleep on plastic encased mattresses, at least here in the USA. So can house dust mites live in such a mattress. Stuffed animals are a huge reservoir of house dust mites. The admittance of a stuffed animal to a baby’s crib may be time dependent with very young children not having such a thing in there sleeping environment due to safety concerns. So did the house dust mite sensitive population have exposure and if so, when in their lives.

As with many good studies, this one gets you to thinking and gets you to ask more questions.

FEL

January 15, 2011 · fleickly · No Comments
Tags: , ,  · Posted in: Allergies, Article Review, Nasal Allergy, Nasal Allergy in Young Children