atopic /ātop″ik/ [Gk, a + topos, not place] , pertaining to a hereditary tendency to experience immediate allergic reactions such as asthma or vasomotor rhinitis because of the presence of an antibody (atopic reagin) in the skin and sometimes the bloodstream. Although it may have a hereditary component, contact with the allergen must occur before the hypersensitivity reaction can develop. −atopy, n.
