Herpes Zoster: Query and Concern

Abstract

In reply: Actually, it is still a prevalent paradigm that immediatetype reactions to iodinated contrast media are mediated by nonimmunologic mechanisms (so-called pseudo-allergic reactions). However, several investigators have recently reported positive skin test results in patients with both immediate and nonimmediate hypersensitivity reactions after contrast media exposure. The tests were often positive to only certain incriminated contrast media but were negative to others. These findings suggest immune mechanisms in a substantial part of such reactions. 1-8 Interestingly, about 50% of patients with positive skin test results were found to have a reaction on primary exposure, which may be best explained by preexistent sensitization to drug-independent, cross-reactive antigens.