Table 1: Causes of asthma exacerbation.

(1) Viral infection (most commonly rhinovirus)
(2) Allergen exposure (tree, grass, and weed pollens; mold; animal dander; dust mites; and cockroach particles)
(3) Exercise
(4) Irritants including environmental tobacco smoke exposure, smoke from wood-burning appliances or fireplaces, strong odors from perfumes, cleaning agents, air pollution, and occupational dust or vapors
(5) Medications (aspirin and other anti-inflammatory drugs, and beta blockers)
(6) Changes in weather (cold air, changes in temperature, and humidity)
(7) Gastroesophageal reflux
(8) Sinusitis