The common cold and asthma

Multimorbidities of asthma, allergies, and airway illnesses in childhood: Chance or not chance?

OBJECTIVES

We investigated patterns of multimorbidities among asthma, allergies, and respiratory illnesses in preschool children. We investigated multimorbidities of lifetime asthma, allergic rhinitis, eczema, food allergy, pneumonia, and ear infections; and multimorbidities of current (in the last year before the survey) wheeze, dry cough, rhinitis, eczema, and common cold during childhood. We further analyzed whether prevalences of these multimorbidities were due to chance.

METHODS

A cross-sectional study was conducted in 72 kindergartens of Shanghai, China. Parents of preschool children were surveyed with a modified ISAAC questionnaire. Observed prevalences (OPs), expected prevalences (EPs), absolute excess comorbidities (AECs), and relative excess comorbidities (RECs) of various combinations of illnesses were calculated to indicate whether the combined illnesses were related.

RESULTS

We analyzed questionnaires for children aged 4-6 years, whose 13,335 questionnaires were the majority of the total 15,266 returned questionnaires (response rate: 85.3%). The studied illnesses were common. For children who had more than three lifetime or current illnesses, OPs tended to be higher than EPs. Most OPs and EPs were higher in boys than in girls, and were higher in children with a family history of atopy (FHA) than in children without FHA. AECs and RECs between boys and girls as well as between children with and without FHA were substantially different.

CONCLUSIONS

Our findings suggest that multimorbidities among childhood asthma, allergies, and respiratory illnesses are likely not random, but rather share etiology. Specific patterns of childhood asthma multimorbidities perhaps differ between boys and girls and between children with and without FHA.

Role of viruses and atypical bacteria in exacerbations of asthma in hospitalized children: a prospective study in the Nord-Pas de Calais region (France)

We studied the role of viruses and atypical bacteria in children hospitalized with exacerbated asthma by a prospective study of children with acute asthma admitted to the Department of Pediatrics in Lille, and to 15 hospitals in the Nord-Pas de Calais region, from October 1, 1998-June 30, 1999. We included children aged 2-16 years with active asthma, defined as three or more recurrent episodes of reversible wheezing. The severity of asthma and of asthmatic exacerbations was recorded. Immunofluorescence assays (IFA) on nasopharyngeal secretions (NPS), serological tests, or both, were used for detection of influenza virus, respiratory syncytial virus (RSV), adenovirus, parainfluenza virus, and coronavirus. Polymerase chain reaction (PCR) assays on NPS were used for rhinovirus and enterovirus. Serological tests for Chlamydia pneumoniae and Mycoplasma pneumoniae were performed. A control group of asymptomatic asthmatic outpatients was examined for respiratory viruses (using IFA and PCR). Eighty-two symptomatic children (mean age, 7.9 years) were examined. Viruses were detected in 38% (enterovirus, 15.8%; rhinovirus, 12%; RSV, 7.3%). Serological tests for atypical bacteria were positive in 10% of patients (C. pneumoniae, 5%; M. pneumoniae, 5%). Among the 27 control subjects (mean age, 7.9 years), one PCR was positive for enterovirus. There was no correlation between severity of chronic asthma or asthmatic exacerbations and the diagnosis of infection. Atypical bacterial pathogen infections were linked with prolonged asthmatic symptoms. In conclusion, we confirmed the high incidence of viral infection in acute exacerbations of asthma, especially enteroviruses or rhinoviruses. Persistent clinical features were more frequently associated with atypical bacterial infections, suggesting that these infections should be investigated and treated in cases of persistent asthmatic symptoms.

[Childhood asthma and viral infection: interactions and therapeutic possibilities]

Rhinovirus infections are the main cause of wheezing in children and adults. Studies carried out with experimental infections report that at least in certain conditions, this infection may spread to the lower respiratory tract as the virus acts on the respiratory epithelium. In vitro experiments with cells from the immune system and lower respiratory tract suggest that the mechanisms of action are directly linked to the production of pro-inflammatory cytokines. Both in vivo and in vitro evidence shows that rhinoviruses may stimulate bronchial epithelial cells to produce cytokines and pro-inflammatory chemokines. They may also stimulate the cholinergic and non-cholinergic nervous system, increasing the production of ICAM-1 and may give rise to a T-lymphocyte non-specific response or to T-lymphocyte replication in direct relation with viral infection. In addition, greater production of cysteinyl leukotrienes has been observed in the secretions of patients with bronchospasm. Experimental infection with Rhinovirus increases clinical symptomatology and bronchial hyperreactivity. The latter is associated with increased eosinophils and cationic proteins in sputum. The above findings suggest that multiple cellular pathways are involved in the induction of exacerbations of asthma induced by the virus. In addition, the possible stimulating role of exposure to allergens in sensitized patients would also increase allergic inflammation. Because of the limited therapeutic efficacy of steroids in reducing exacerbations, new treatment strategies based on greater insight into the physiopathology of the role of viruses in asthma are needed.