The interplay between stress and allergy
The nervous and immune systems are interrelated and interacting. Allergy is characterized by a cataract of molecular, cellular and immunological responses activated through specific IgE production to variety of allergens, thus producing symptoms. Stress is a generalized body response to threatening external or internal demands, mobilizing physiological and psychological resources in order to deal with them. Stress activates neuroendocrine and sympathetic system through catecholamine and cortisol secretion, hence influencing the immune system via alteration of Th1/Th2 balance and switching the immune response towards Th2 direction, as in allergic disease. Stressors are capable of modifying the allergic response. In genetically predisposed individuals, stress may both induce the onset of allergic disease and participate in the exacerbation of preexisting allergy. Furthermore, allergic symptoms may lead to a new balance of the cytokine immunoregulation. In conclusion, it seems that a reciprocal influence and relationship between allergic diseases and psychoneuroimmunoendocrine axis exists.