Stress and inflammation in exacerbations of asthma

In this mini-review, we outline a model depicting the immunologic mechanisms by which psychological stress can exacerbate clinical symptoms in patients with asthma. This model highlights the importance of both social and physical exposures in the exacerbation of asthma symptoms. The basic premise of the model is that psychological stress operates by altering the magnitude of the airway inflammatory response that irritants, allergens, and infections bring about in persons with asthma. The biological pathways for how stress amplifies the immune response to asthma triggers include the hypothalamic-pituitary-adrenal (HPA) axis, the sympathetic-adrenal-medullary (SAM) axis, and the sympathetic (SNS) and parasympathetic (PNS) arms of the autonomic nervous system. Empirical evidence for this model is reviewed, and conclusions and future research directions are discussed. (C) 2007 Elsevier Inc. All rights reserved.