IGHE and Alzheimer disease: Fungi are generally thought to be less influential in the pathogenesis of AD; however, Malassezia hypersensitivity has been implicated in both human and canine AD through patch testing, IgE studies and responsiveness to antifungal therapy (Morris, Olivier and Rosser 1998; Farver et al. 2005; Bond et al. 2006; Casagrande et al. 2006; Kato et al. 2006; Zhang et al. 2011a).