Clinical and Anamnestic Characteristics of Bronchoobstructive Syndrome in Children with Atopic Dermatitis

The dissertation is devoted to the study of the clinico-anamnestic features of bronchoobstructive syndrome in children suffering from atopic dermatitis and to the evaluation of risk factors for the development of bronchial asthma in this group of patients. The relevance of the research is due to the high prevalence of atopic dermatitis in childhood and the established association between this disease and the subsequent development of bronchial asthma in a significant proportion of children. The work was carried out on the basis of materials of a retrogressive clinico-functional observation for the period 1988–2001 and includes an analysis of clinical variants of the course of bronchoobstructive syndrome, the identification of key risk factors, and the evaluation of the effectiveness of specific immunotherapy as a method of primary prevention of bronchial asthma.

RELEVANCE

Atopic dermatitis is an urgent problem of pediatrics, as its onset in most cases occurs in early childhood, and in 60–70% of children it is noted within the first year of life. Atopic dermatitis is one of the most prevalent allergic diseases of childhood, with a prevalence among children in economically developed countries ranging from 10% to 28%, and the share of atopic dermatitis among allergic diseases constitutes 50–75% [4]. The steady progressive increase in the incidence of atopic dermatitis in children in recent years, the unfavorable pathomorphosis of its clinical course, and the growing number of disabling forms are only some of the aspects determining the high relevance of the problem. The acuteness of the situation is also due to the fact that in 40–50% of children suffering from atopic dermatitis, bronchial asthma, pollinosis, and/or allergic rhinitis subsequently develop [4].

Bronchial asthma belongs to the most prevalent chronic diseases of childhood, leading to frequent disability of patients and requiring significant expenditures on treatment. The prevalence of bronchial asthma in the pediatric population in various regions of the world reaches 10–15%, and the number of patients is 100–150 million. Among the pediatric population of Russia, the prevalence of bronchial asthma ranges from 3% to 15%. In recent years, worldwide, including in Russia, a trend toward increasing morbidity of bronchial asthma in children and its more severe course has been noted. In 10–20% of children with atopic dermatitis, bronchial asthma subsequently develops [37, 136, 170, 196]. In connection with this, the aim of the study was to identify risk factors for the development of bronchial asthma in children suffering from atopic dermatitis, in order to develop and employ effective methods of primary prevention of bronchial asthma, which would substantially reduce the frequency of this pathology among children with atopic dermatitis.

OBJECTIVE OF THE RESEARCH: To establish the patterns of development of bronchoobstructive syndrome in children with atopic dermatitis, through a clinico-functional retrogressive study, and to evaluate the effectiveness of specific immunotherapy from the standpoint of primary prevention of bronchial asthma in this group of patients.

TASKS:

1. To analyze the clinico-anamnestic features of bronchoobstructive syndrome in children with atopic dermatitis.

2. To evaluate the dynamics of atopic dermatitis in children based on the results of a retrogressive analysis for the period 1988–2001.

3. To identify risk factors for the development of bronchial asthma in children with atopic dermatitis.

4. To evaluate the effectiveness of primary prevention of bronchial asthma in the group of patients with atopic dermatitis by means of specific immunotherapy, based on the results of a retrogressive analysis for the period 1988–2001.

5. To present recommendations for the early identification of predictors of bronchial asthma in patients with atopic dermatitis and measures of primary prevention.

SCIENTIFIC NOVELTY

For the first time, clinical variants and outcomes of bronchoobstructive syndrome in children with atopic dermatitis were identified: transient bronchoobstructive syndrome and persistent bronchoobstructive syndrome leading to the formation of bronchial asthma. Transient bronchoobstructive syndrome in children who initially had atopic dermatitis is characterized by an early onset (within the first 6 months of life), in some cases the absence of hereditary predisposition to atopic pathology, and resolves by the age of 6–7 years. Persistent bronchoobstructive syndrome, leading to the formation of bronchial asthma in patients with atopic dermatitis, has the following features, in contrast to patients with bronchial asthma who have no history of atopic dermatitis: late onset of bronchoobstructive syndrome (at the age of 4–5 years), more frequent manifestation in the form of acute attacks, a more severe course compared to patients without atopic dermatitis, and the involvement of food allergens as more frequent triggers both of initial disease manifestations and of subsequent exacerbations.

Risk factors for the development of bronchial asthma in children with atopic dermatitis were established: male sex, hereditary predisposition to atopic pathology (especially along the maternal line and along both lines of descent), complicated course of pregnancy (toxemia), prematurity (birth weight less than 2500 g.), frequent acute respiratory infections in the first year of life, early onset of atopic dermatitis (within the first 6 months of life), late onset of bronchoobstructive syndrome (at the age of 4–5 years), and allergic rhinitis. The risk of developing bronchial asthma in children with atopic dermatitis was 23.76%.

Risk factors exerting the greatest contribution to the development of bronchial asthma in patients with atopic dermatitis were analyzed. The most significant were identified as two factors: the factor of "age of onset of bronchoobstructive syndrome" and the factor of "hereditary predisposition to atopic pathology." It was demonstrated that with each additional month of age at the onset of bronchoobstructive syndrome, the chance of developing bronchial asthma increases by 23.7%, and the presence of hereditary predisposition to atopic pathology (along the maternal line and along both lines of descent) also increases the chance of developing bronchial asthma.

For the first time, the protective role of specific immunotherapy in the development of bronchial asthma in children with atopic dermatitis was proven (a 6.8-fold reduction in the frequency of bronchial asthma following the administration of specific immunotherapy). Within the framework of a 10-year prospective observation, a reliable decrease in the level of immunoglobulin E in serum and the degree of household and epidermal sensitization in patients with atopic dermatitis after the administration of specific immunotherapy was established.

PRACTICAL SIGNIFICANCE

New data regarding risk factors for the development of bronchial asthma in children with atopic dermatitis were demonstrated, which can be employed in the conduct of primary prevention of the disease in this group of children.

Evidence of the effectiveness of specific immunotherapy, its protective influence on the formation of bronchial asthma in patients with atopic dermatitis, was obtained, which can be used in the development of programs for primary prevention of bronchial asthma in this category of patients.

POSITIONS TO BE DEFENDED:

1. Bronchoobstructive syndrome in atopic dermatitis has features represented by a complex of clinico-anamnestic characteristics of the disease.

2. Specific immunotherapy makes it possible to substantially reduce the risk of the formation of bronchial asthma in patients with atopic dermatitis.

PRESENTATION:

The main results of the work were reported and discussed at conferences of young scientists (Tomsk, 2003 and 2004), at the problem commission on pediatrics, at conferences of the Department of Faculty Pediatrics with a Course of Pediatric Diseases of the Medical Faculty of the State Educational Institution of Higher Professional Education "Siberian State Medical University" of the Ministry of Health of Russia (2002, 2003, 2004). The materials of the dissertation were discussed in 15 publications, of which 12 are full-text journal articles (1 in the central press), 1 methodological recommendation bearing the designation of the State Educational Institution of Higher Professional Education "Center for Medical and Preventive Work of the Ministry of Health of the Russian Federation" "Bronchoobstructive Syndrome in Children of Early Age," and 2 theses in the materials of international conferences.

IMPLEMENTATION:

The obtained results are used in the work of the allergological department of the regional children's hospital of the city of Tomsk and the regional children's center of allergology and immunology of the regional children's hospital of the city of Tomsk. The materials of the conducted studies were included in the training programs for students of the 4th and 5th courses of the pediatric, medical, and medical-biological faculties of the State Educational Institution of Higher Professional Education "Siberian State Medical University" of the Ministry of Health of Russia.

STRUCTURE AND VOLUME OF THE WORK:

The dissertation is built on a traditional plan and consists of an introduction, 5 chapters, a discussion of the research results, conclusions, practical recommendations, an index of literature containing 89 foreign and 109 domestic sources, and an appendix. The work is presented on 152 pages of typed text, illustrated by 24 tables and 10 figures.