Natural course of asthma and allergy in childhood

Asthma prediction in school children; the value of combined IgE-antibodies and obstructive airways disease severity score

BACKGROUND

Allergic sensitisation increases the risk for asthma development. In this prospective birth cohort (Environment and Childhood Asthma) study, we hypothesized that combining quantitative measures of IgE antibodies (Sigma-IgE) and Severity score of obstructive airways disease (OAD) at 2 years of age (Severity score) is superior to predict current asthma (CA) at 10 years than either measure alone. Secondarily, we assessed if gender modified the prediction of CA.

METHODS

A follow-up study at 10 years of age was performed in 371 2-year-old children with recurrent (n = 219) or no (n = 152) bronchial obstruction with available serum analysed for Sigma-IgE to common food and inhalant allergens through a panel test, Phadiatop Infant) (Phadia, Uppsala, Sweden). Clinical variables included allergic sensitisation and exercise testing to characterise children with CA vs not CA at 10 years and the Severity score (0-12, 0 indicating no OAD) was used to assess risk modification.

RESULTS

Severity score alone explained 24% (Nagelkerke R(2) = 0.24) of the variation in CA, whereas Sigma-IgE explained only 6% (R(2) = 0.06). Combining the two increased the explanatory capacity to R(2) = 0.30. Gender interacted significantly with Sigma-IgE; whereas Severity score predicted CA in both genders, the predictive capacity of Sigma-IgE for CA at 10 years was significant in boys only.

CONCLUSION

Combining Sigma-IgE to inhalant allergens and Severity score at 2 years was superior to predict asthma at 10 years than either alone. Severity score predicted CA in both genders, whereas Sigma-IgE significantly predicted CA in boys only.

Pharmaceutical treatment strategies for childhood asthma

PURPOSE OF REVIEW

Although great improvement has been obtained in quality of life and mastering of illness by asthmatic children over recent decades, controversies still exist related to asthma treatment. The objective of the present article is to discuss such controversies.

RECENT FINDINGS

Results from recent publications related to childhood asthma treatment question existing dogmas. Important for prescribing correct treatment to children is correct diagnosis. Phenotypes of childhood asthma related to treatment decisions are discussed. Early use of inhaled steroids in young children is still debated as well as the preference of inhaled long-acting beta2-agonists versus leukotriene receptor antagonists as add on to inhaled steroids. When present, both allergic rhinitis and asthma should be treated to obtain improved control. Also as regards the treatment of exercise-induced asthma in children, new results concerning use of leukotriene receptor antagonists is discussed as well as the acute treatment in infants with bronchial obstruction.

SUMMARY

There are still several controversies regarding treatment of the asthmatic child. New studies designed specifically for children are needed to solve these questions. One cannot rely on studies performed in adults for treatment in children. New studies designed for childhood asthma are needed to solve these controversies.

Specific immunotherapy is effective in the prevention of new sensitivities

BACKGROUND

Allergen specific immunotherapy is the only specific and curative approach in the treatment of IgE-mediated allergic diseases such as bronchial asthma and allergic rhinitis. The safety and clinical efficacy of this treatment are well documented but data on the prevention of new sensitizations remain scarce.

OBJECTIVE

To demonstrate the efficacy of specific immunotherapy in allergic respiratory diseases in childhood and to determine whether this treatment prevents the development of new sensitizations in children sensitized to house dust mite or pollen species.

METHODS

Fifty-six patients received specific immunotherapy (43 sensitive to house dust mite and 13 sensitive to pollen). Fifty-one patients not receiving immunotherapy but treated with pharmacotherapy were enrolled in the control group. The patients were followed-up for at least 4 years and treatment efficacy and the development of new sensitizations were compared between the two groups.

RESULTS

The number of patients with symptoms was significantly decreased in both groups at the end of the treatment period. No new sensitizations were found in 35 of the 43 (81.39 %) patients in the house dust mite immunotherapy group and in 10 of 13 (76.92 %) patients in the pollen immunotherapy group. In contrast, 20 of 51 (39.21 %) patients in the control group showed new sensitizations. The difference between the house dust mite and pollen immunotherapy groups and the control group in this parameter was statistically significant (p = 0.033).

CONCLUSION

Our data demonstrate that administration of specific immunotherapy in allergic patients significantly reduced symptoms and the development of new sensitivities.

[Association between atopic dermatitis, allergic rhinitis and asthma in schoolchildren aged 13-14 years old]

BACKGROUND

Atopic dermatitis is closely related to other atopic diseases, especially asthma and allergic rhinitis. Although there is a certain agreement that suffering from atopic eczema predisposes to asthma and allergic rhinitis, the risk of developing these diseases should be quantified in populations following a standardized method, which is the objective of this study.

METHOD

Using the questionnaire from the International Study of Asthma and Allergy in Childhood (ISAAC), we performed a cross-sectional study of all schoolchildren aged 13 and 14 years old in the city of Cartagena (Murcia, Spain). The relationship between atopic dermatitis and its severity with asthma, allergic asthma, and allergic rhinitis was analyzed.

RESULTS

Quantification of risk showed that schoolchildren with atopic eczema had a 3-fold risk of allergic rhinitis (OR: 3.33; 95 % CI: 2.45-4.54), a 4-fold risk of asthma (OR: 3.85; 95 % CI: 2.74-5.42) and a 5-fold risk of allergic asthma (OR: 4.91; 95 % CI: 3.17-7.59) compared with schoolchildren without atopic eczema. The severity of eczema was also directly related to that of asthma and rhinitis.

Therapeutic strategies for allergic airways diseases

Asthma and allergic rhinitis are airways allergic diseases and different aspects of these diseases are discussed in this paper. Both diseases require specific treatment but the airways are a continuum and it has been shown that concomitant treatment in patients suffering from both diseases has a better effect than treating only one of the diseases. Furthermore, treatment of allergic rhinitis in asthmatic patients reduces the risk of hospital admission due to asthma and improves bronchial hyper-responsiveness. Anti-inflammatory therapy, particularly with local steroids, is the single most important treatment for airways allergic diseases. Some studies have shown the importance of starting early after diagnosing asthma but the issue of how early in life to start inhaled steroids is still being debated. Also leukotriene antagonists have been shown to have beneficial effects in many patients and can be used in conjunction with inhaled steroids. Combination therapy with inhaled steroids and inhaled beta(2)-agonists has been shown to be effective in adults but this has not yet been fully documented in children. Optimal treatment of exercise-induced asthma is important to enable children and adolescents to fulfill their developmental possibilities. Allergy vaccination has traditionally been used for treating airways allergic diseases. It is often given for allergic rhinitis when pharmacotherapy is not providing full symptom control. One recent study has suggested that allergy vaccination may possibly help to prevent the development of asthma in the child with allergic rhinitis. More research is needed on asthma allergy vaccination. Concordance with treatment may often be difficult and efforts should be taken to ensure the best concordance possible.

Atopic diseases of childhood

PURPOSE OF REVIEW

The incidence of atopic diseases, including atopic dermatitis, allergic rhinitis, and asthma, has increased in developed countries over the past several decades. These diseases comprise a large component of general pediatric practice. This review will highlight some of the recent advances in understanding the pathogenesis and natural history of these diseases, as well as the current approaches to the treatment of children with atopic diseases.

RECENT FINDINGS

Recent studies have identified multiple risk factors for the development and progression of atopic diseases. As a result, much research is focused on identifying therapies that can be initiated at a young age to prevent disease progression. New treatment options have become available in recent years, such as topical immunomodulators for atopic dermatitis, leukotriene antagonists for seasonal allergic rhinitis, and alpha-immunoglobulin E therapy for asthma. The importance of viewing allergic rhinitis and asthma as disorders of a single airway has been emphasized. Finally, an update on the national asthma guidelines was recently released in an effort to promote optimal asthma care.

SUMMARY

This review summarizes many of the recent advances in the diagnosis and treatment of atopic diseases in children. Although not intended to be a comprehensive review of this broad field, it provides a framework for appreciating the complexity of these diseases and for effectively managing them.

Atopic diseases of childhood

The atopic diseases of childhood consist of the triad of asthma, allergic rhinitis, and atopic dermatitis. All share a common pathogenesis, being mediated by IgE, and are frequently present together in the same individual and family. These disorders and their comorbidities comprise a large component of general pediatric practice and their incidence in developed countries has been increasing over the past few decades. They are a leading reason for clinic and emergency room visits, as well as hospital admissions. They have the potential to interfere with education, physical activity, socialization, and self-esteem. Fortunately, we now have a reasonable armamentarium of maintenance medications available to help control these disorders and improve the quality of life for children suffering from them. In addition, early diagnosis and aggressive management of these disorders seem to offer the possibility of altering their natural history. As such, developing a sensible approach to the diagnosis and treatment of these disorders in an outpatient setting is essential. In this review, I summarize the most current literature and provide a framework for effectively diagnosing and managing these disorders.

Prevention of new sensitizations in asthmatic children monosensitized to house dust mite by specific immunotherapy. A six-year follow-up study

BACKGROUND

Specific immunotherapy (SIT) is a recognized way of treating IgE-mediated respiratory diseases. The clinical outcome is usually better in allergic children than in adults.

OBJECTIVE

To increase our knowledge of the ability of SIT to prevent the onset of new sensitizations in monosensitized subjects, so far poorly documented.

METHODS

134 children (age range 5-8 years), who had intermittent asthma with or without rhinitis, with single sensitization to mite allergen (skin prick test and serum-specific IgE), were enrolled. SIT was proposed to all the children's parents, but was accepted by only 75 of them (SIT Group). The remaining 63 children were treated with medication only, and were considered the Control Group. Injective SIT with mite mix was administered to the SIT Group during the first three years and all patients were followed for a total of 6 years. All patients were checked for allergic sensitization(s) by skin prick test and serum-specific IgE every year until the end of the follow-up period.

RESULTS

Both groups were comparable in terms of age, sex and disease characteristics. 123 children completed the follow-up study. At the end of the study, 52 out of 69 children (75.4%) in the SIT Group showed no new sensitization, compared to 18 out of 54 children (33.3%) in the Control Group (P < 0.0002). Parietaria, Gramineae and Olea were the most common allergens responsible for the new sensitization(s).

CONCLUSIONS

According to our data, SIT may prevent the onset of new sensitizations in children with respiratory symptoms monosensitized to house dust mite (HDM).

Does allergen immunotherapy alter the natural course of allergic disorders?

Allergy in patients with atopy is caused by clinical adverse reactions to environmental antigen, which is often associated with allergen-specific immunoglobulin (Ig)E production. Since allergy reflects an inappropriate immunological reaction, a therapeutic approach related to immunology is likely to actively alter the natural course of allergic disorders. Allergen immunotherapy, known at various times as desensitisation or hyposensitisation, is very recently defined by the World Health Organization as therapeutic vaccines for allergic diseases. At present, it has become a common clinical practice in selected patients for the treatment and prevention of the recurrence of allergic disorders caused by insect venoms and has proven to be effective in changing the course of allergic responses induced by grass and tree pollen, animal hair and dander, house dust mite and mold, as demonstrated by improvement in clinical symptoms, skin prick test and medication scores. Reported effects of allergen immunotherapy on the natural course of allergic disorders include (i) prevention of reaction following re-sting in insect venom allergy; (ii) prevention or decrease the rate of the natural progress of allergic rhinitis to asthma; and (iii) inhibition of new sensitisation in monosensitised children. Many aspects of the immune responses associated with allergic disorders, including antibody production, cytokine secretion, T cell activation and local inflammatory reactions, are found to be significantly altered during and/or after immunotherapy. Specifically, the ratio of allergen-specific IgG4 to IgG1 correlates well with positive clinical outcome caused by allergen immunotherapy in patients with pollen-allergy. Allergen immunotherapy affects the cytokine profile of allergen-specific T cells and switches T(H)2 type immune responses in patients with atopy towards T(H)0 or T(H)1 type responses. Although the changes in the absolute value of T(H)1 or T(H)2 cytokines appear quite variable, the increase in the ratio of T(H)1/T(H)2 cytokines is very consistent among published reports, especially in the late stage of treatment. Accumulating evidence indicates that appropriate immunotherapy prevents the onset of new sensitisation and prevents the progress of allergic rhinitis to asthma. Although the changes in B cell and T cell responses, especially IgG antibodies and T(H)1/T(H)2 cytokine production, may be the major mechanism underlying the clinical efficacy of allergen immunotherapy and the prevention of the development of allergic phenotypic changes, multiple mechanisms may be involved in the outcome of alteration of the natural course of allergic disorders.

Sensitization to hen's egg at the age of twelve months is predictive for allergic sensitization to common indoor and outdoor allergens at the age of three years

BACKGROUND

Specific predictors for atopic sensitization in early infancy are prerequisites for preventive intervention studies.

OBJECTIVE

To identify predictors of allergic sensitization to common aeroallergens in infancy, 1314 children in five German cities were followed up from birth (1990) to the age of 3 years.

METHODS

Blood samples were taken from cord blood and at follow-up visits at the ages of 1, 2, and 3 years. Total serum IgE and specific IgE antibodies to common food and inhalant allergens were determined.

RESULTS

Among our study population, risk factors for sensitization to indoor and/or outdoor allergens at the age of 3 years were a positive family history, the presence of hen's egg-specific IgE antibodies (> or = 0.35 kU/L), and increased log- [total IgE] levels at the age of 12 months. Elevated cord blood IgE was not associated with sensitization to inhalant allergens at the age of 3 years. Egg-specific IgE greater than 2 kU/L in combination with a positive family history of atopy was a highly specific (specificity, 99%) and predictive (positive predictive value, 78%) marker for sensitization to inhalant allergens at 3 years of age.

CONCLUSIONS

Hen's egg-specific IgE at the age of 12 months is a valuable marker for subsequent allergic sensitization to allergens that cause asthma, allergic rhinitis, and atopic dermatitis.