Allergic rhinitis in children

Cardiac autonomic imbalance in children with allergic rhinitis

The involvement of autonomic imbalance has been reported in the pathogenesis of hypersensitivity reactions. Allergic diseases are more frequent in children and some of predisposing factors may be changed according to the increasing age, but the involvement of autonomic imbalance has not been investigated in pediatric population. In this cross-sectional, case-control study, we evaluated the autonomic system by measuring heart rate variability (HRV) in pediatric patients with allergic rhinitis. Thirty-five pediatric patients with allergic rhinitis and 36 healthy children (mean age 11 +/- 2.7, and 12 +/- 3 years, respectively) were enrolled in the study. Age and gender were not different between the groups. The diagnosis of allergic rhinitis was based on the history, symptoms, and skin prick tests. Participants with acute infection, nasal polyposis, bronchial asthma, and any other medical problems, assessed by history, physical examination and routine laboratory tests, were excluded. Twenty-four hour ambulatory electrocardiographic recordings were obtained, and the time domain and frequency domain indices of HRV were analyzed. We found significant increase in calculated HRV variables in children with allergic rhinitis compared to controls, which reflect parasympathetic tones, such as number of R-R intervals exceeding 50 ms, root mean square of successive differences between normal sinus R-R intervals, the percentage of difference between adjacent normal R-R intervals, and high frequency. These results indicate that HRV is increased, which implies sympathetic withdrawal and parasympathetic predominance. We propose that autonomic imbalance may be involved in the pathophysiology of allergic rhinitis in pediatric patients.

The association of allergic symptoms with sensitization to inhalant allergens in childhood

Although it is generally agreed that sensitization is an important risk factor for allergic diseases, the extent to which sensitization accounts for allergic symptoms in children is controversial. As part of the Aalst Allergy Study, this cross-sectional study investigated the prevalence of allergic symptoms and their association with sensitization in an unselected population of Flemish children aged 3.4-14.8 yr. Skin prick testing with the most common aeroallergens was performed and allergic symptoms were documented by a parental questionnaire. In the children older than 6 yr, a significant association of current wheezing, current dyspnea, airway hyperreactivity, rhinoconjunctivitis, and current eczema with sensitization was found, while in the pre-school children these associations were less pronounced. The association with sensitization was strongest for rhinoconjunctivitis and current respiratory symptoms - the association was less striking for children with current eczema. The impact of a positive family history of allergy on the association with sensitization was more important for eczema than for the other analyzed allergic symptoms. Persistent and late-onset wheezers were significantly more likely than non-wheezers and transient early wheezers to be associated with sensitization and a personal history of rhinoconjunctivitis. Late-onset wheezing was associated with a positive family history of allergy, while transient early wheezing was associated with day-care attendance. An association with eczema was found for all three childhood wheezing phenotypes. The association of allergic symptoms with sensitization is significant in the older but less pronounced in pre-school children and is more pronounced for current allergic symptoms. Diagnosis and disease definition of allergy symptoms remains difficult at pre-school age. The influence of a positive family history of allergy on the association of the respective allergic symptoms with sensitization was most important for eczema. Our data confirm the atopic characteristics of the different wheeze phenotypes.

Rhinitis in pre-school children: prevalence, association with allergic diseases and risk factors

BACKGROUND

The aim of our study was to assess the prevalence of rhinitis, sneezing, runny or blocked nose apart from colds in a pre-school children population and to evaluate the risk factors and relationship with allergic diseases and sensitization.

METHODS

Eighteen nursery schools were randomly selected. The International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire (WQ) was distributed and filled by parents of pre-school children (3-5 years). The allergic sensitization to common aeroallergens and foods was evaluated by skin prick test (SPT). chi2 tests were used to compare proportions between rhinitic and non-rhinitic children.

RESULTS

One thousand four hundred and two (92%) valuable questionnaires were returned. Prevalence of rhinitis in the last 12 months was 16.8%. Rhinitic children compared to non-rhinitic children presented a significant increase of diagnosed asthma (20.8% vs. 6.2%, P<0.001), lifetime wheezing (43.2% vs. 21.6%, P<0.001), wheezing in the last 12 months (25.0% vs. 9.4%, P<0.001), atopic dermatitis (22.9% vs. 13.9%, P<0.001) and allergic sensitization (29.9% vs. 13.7%, P<0.001). Sensitization to grass pollen and house dust mites were significant risk factors for rhinitis (P<0.01). A family history of atopy, having pets at home, male gender and greater age were significant risk factors for rhinitis, but not smoking exposure, sharing a bedroom or breastfeeding.

CONCLUSIONS

In pre-school children rhinitis has a strong association with wheezing symptoms, asthma and atopic dermatitis. Allergic sensitization is a risk factor for rhinitis and should be evaluated even in pre-school children.