Histamine-induced middle ear effusion and mucosal histopathology in the guinea pig

It has been suggested that immune responses and resultant generation or release of inflammatory mediators play a role in otitis media with effusion (OME). To explore the potential of one such mediator to contribute to OME, the effects of histamine injected into the middle ear cavity were examined. Injection of histamine into the guinea pig middle ear was found to produce dilation and endothelial disjunction in capillaries, leading to striking mucosal edema and effusion which persisted for at least several hours. This response could be partially blocked by pretreatment with either H1 or H2 antihistamines. It is suggested that histamine released during immune responses in the middle ear may contribute to the formation of effusion and submucosal edema as observed in OME.