| Neurogenic Switching: A Hypothesis for a Mechanism for Shifting the Site of Inflammation in Allergy and Chemical Sensitivity William J. Meggs Department of Emergency Medicine, East Carolina University School of Medicine, Greenville, NC 27858 USA and New York City Poison Center, New York, NY 10016 USA Abstract
Neurogenic switching is proposed as a hypothesis for a mechanism by which a stimulus at one site can lead to inflammation at a distant site. Neurogenic inflammation occurs when substance P and other neuropeptides released from sensory neurons produce an inflammatory response, whereas immunogenic inflammation results from the binding of antigen to antibody or leukocyte receptors. There is a crossover mechanism between these two forms of inflammation. Neurogenic switching is proposed to result when a sensory impulse from a site of activation is rerouted via the central nervous system to a distant location to produce neurogenic inflammation at the second location. Neurogenic switching is a possible explanation for systemic anaphylaxis, in which inoculation of the skin or gut with antigen produces systemic symptoms involving the respiratory and circulatory systems, and an experimental model of anaphylaxis is consistent with this hypothesis. Food-allergy-iducing asthma, urticaria, arthritis, and fibromyalgia are other possible examples of neurogenic switching. Neurogenic switching provides a mechanism to explain how allergens, infectious agents, irritants, and possibly emotional stress can exacerbate conditions such as migraine, asthma, and arthritis. Because neurogenic inflammation is known to be triggered by chemical exposures, it may play a role in the sick building syndrome and the multiple chemical sensitivity syndrome. Thus neurogenic switching would explain how the respiratory irritants lead to symptoms at other sites in these disorders. Key words: allergy, anaphylaxis, arthritis, asthma, chemical sensitivity, food allergy, inflammation, migraine, neurogenic inflammation, substance P. Environ Health Perspect 103:54-56 (1995) http://ehpnet1.niehs.nih.gov/docs/1995/103-1/meggs.html
Address correspondence to W.J. Meggs, Room 4W54, Brody Building, Department of Emergency Medicine, East Carolina University, Greenville, NC 27858 USA. Received 1 July 1994 ; accepted 14 September 1994.
The full version of this article is available for free in HTML format. |
