The September epidemic of asthma exacerbations in children: a search for etiology.
BACKGROUND
Predictable peaks of asthma exacerbation requiring hospital treatment, of greatest magnitude in children and of uncertain etiology, occur globally after school returns.


OBJECTIVE
We wished to determine whether asthmatic children requiring emergency department treatment for exacerbations after school return in September were more likely to have respiratory viruses present and less likely to have prescriptions for control medications than children with equally severe asthma not requiring emergent treatment.


METHODS
Rates of viral detection and characteristics of asthma management in 57 (of 60) children age 5 to 15 years presenting to emergency departments with asthma in 2 communities in Canada between September 10 and 30, 2001, (cases) were compared with those in 157 age-matched volunteer children with asthma of comparable severity studied simultaneously (controls).


RESULTS
Human picornaviruses were detected in 52% of cases and 29% of controls ( P = .002) and viruses of any type in 62% of cases and 41% of controls ( P = .011). Cases were less likely to have been prescribed controller medication (inhaled corticosteroid, 49% vs 85%; P < .0001; leukotriene receptor antagonist, 9% vs 21%; P = .04).


CONCLUSIONS
Respiratory viruses were detected in the majority of children presenting to emergency departments with asthma during the September epidemic of the disease and in a significant minority of children with asthma in the community. The latter were more likely to have anti-inflammatory medication prescriptions than children requiring emergent treatment. Such medication may reduce the risk of emergency department treatment for asthma during the September epidemic.
Johnston
Neil W
NW
Firestone Institute for Respiratory Health, St. Joseph's Healthcare and McMaster University, Hamilton, Ontario, Canada. njohnsto@sympatico.ca
Johnston
Sebastian L
SL
Duncan
Joanne M
JM
Greene
Justina M
JM
Kebadze
Tatiana
T
Keith
Paul K
PK
Roy
Madan
M
Waserman
Susan
S
Sears
Malcolm R
MR
D000280:Administration, Inhalation; D000293:Adolescent; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000453:epidemiology / Q000821:virology*; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006761:Hospitals; D006801:Humans; D006889:Hydroxycorticosteroids / Q000627:therapeutic use; D020024:Leukotriene Antagonists / Q000627:therapeutic use; D008297:Male; D010849:Picornaviridae / Q000302:isolation & purification*; D010850:Picornaviridae Infections / Q000150:complications* / Q000188:drug therapy; D012307:Risk Factors; D012621:Seasons; D011795:Surveys and Questionnaires
D018927:Anti-Asthmatic Agents; D006889:Hydroxycorticosteroids; D020024:Leukotriene Antagonists