11/5/03 Predictors of life-threatening asthma flares in childrenSummaryA number of characteristics of adult asthmatics who experience life-threatening episodes (LTE) of asthma have been described. However, less is known about the characteristics of children who have manifested LTE. Roberts et al of St. Mary's Hospital in London, UK compared a number of characteristics in: 1) 19 children (ages 1-16 years) with a history of mechanical ventilation during a previous LTE associated with a severe asthma flare and 2) a control group of 38 asthmatic children matched for age, gender and ethnicity who had never had an LTE. After a regression analysis, they found that there was in increased likelihood of LTE associated with several characteristics. However, only 1) previous frequent in-patient admissions for asthma and 2) presence of food allergy were independently associated with LTE (Odds ratios of 9.85 and 5.89 respectively). Food allergy was present in 50% of the children with LTE but in only 10% of the control asthma group. The authors concluded that the presence of poorly controlled asthma and food allergy were risk factors for LTE. Such children should be watched particularly closely to prevent LTE. Reference J Allergy Clin Immunol 2003; 112:168-74 Editor's Comments These findings are of considerable interest and practical importance in possibly preventing LTE in childhood asthmatics. The finding that previous repeated hospital admissions for asthma flares is a risk factor for LTE is not surprising. Such a history may indicate that the child is one of the minority of asthmatics who are very "brittle." The child may also be exposed to high concentrations of irritants (e.g. tobacco smoke) and/or be poorly compliant with asthma controller therapy with a reliance mainly on "rescue" use of inhaled beta agonists. The latter characteristics may explain the increased association of LTE in adults with lower socio-economic circumstances. Whether the food allergy itself is responsible for LTE or is just a marker of stronger atopic reactivity is not defined. Previous studies in children do suggest that multi-allergen sensitivity is associated with greater bronchial hyper-reactivity. One study in adult asthmatics suggested that a previous history of a food allergy-induced asthma attack was a risk factor for a subsequent LTE. Another recent study identified the presence of food allergy as a risk factor for life-threatening asthma exacerbations (Pediatr Respir Rev 2003; 4:205-12 ). More investigation is required. However, this sub-population of childhood asthmatics bears particular attention.
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