Why children with asthma get sick in September?

There seems to be a predictable increase in ED visits and hospital admissions for childhood asthma in North America every September which is likely related to return to school.

The authors of this article in the Journal of Allergy and Clinical Immunology point to the following causes of this "September phenomenon":

1. Rhinovirus infection -- likely the major trigger of the increase in asthma exacerbations on return to school. Respiratory tract viruses have emerged as the most frequent triggers for exacerbations in both children and adults (JACI, 2011).

2. Low use of controller asthma medications (inhaled corticosteroids) during summer.



Asthma Society of Canada video, Aug 19, 2011: Did you know that 25% of all children's asthma hospitalizations occur in the month of September? This is known as the September Peak, and is linked to the back-to-school period, weather, hygiene, and poor asthma management. This video tells you how to manage your asthma properly to avoid becoming a September statistic.

The video features Malcolm Sears, Professor, Division of Respirology, Department of Medicine, McMaster University.

Asthma cases surge as kids go back to school - National Jewish Health - YouTube http://bit.ly/16UWHtz



Mnemonic for causes of pediatric asthma exacerbation in the fall: CRIME:

Corticosteroid vacation during summer - many patients stop inhaled corticosteroids (ICS) during summer
at exposure from clothes/hair of classmates

Ragweed

Infections - viruses

Mold from AC ducts

Exposure to cat allergen from classmates in classroom

References:

Understanding the September asthma epidemic. Sears MR, Johnston NW. J Allergy Clin Immunol. 2007 Jul 19.
Back-to-school Season Can be Tough on Kids with Asthma. University of Michigan Health System, 08/2007.

Allergic sensitization is associated with rhinovirus-, but not other virus-, induced wheezing in children. http://goo.gl/PghX
Rhinoviruses: markers of, or causative for, recurrent wheeze and asthma? ERJ 2012.
Image source: Molecular surface of a rhinovirus, Wikipedia, GNU Free Documentation License.

Comments from Twitter:

@allergydoc4kidz also peak in outdoor mold spores across prairies early sept, and likely increased second hand cat allergen exposure in schools