Allergy

Allergy is the term used for a collection of diseases mediated by immunologic mechanisms. Allergic disorders include allergic rhinitis, conjunctivitis, asthma, urticaria, angioedema, food allergy, drug allergy, and anaphylaxis. The prevalence of allergic diseases has been increasing in recent times. They are a major cause of morbidity and decreased quality of life. The development of allergic diseases is influenced by heritable and environmental factors. Diagnosis often involves documenting responses to allergen such as in skin testing, radioallergosorbant allergen testing, or bronchial provocation testing. Allergic disorders share the common pathology of inflammation of affected tissues. Allergy requires sensitization to an allergen and response on re-exposure to that same allergen. Pathogenesis involves production and release of cytokines, chemokines, and lipid mediators which cause tissue damage and recruit inflammatory cells. Current therapies include allergen avoidance, antihistamines, leukotriene modifiers, corticosteroids, phosphodiesterase inhibitors, humanized monoclonal anti-IgE, and immunotherapy.