Understanding Insect Bite Hypersensitivity in Horses: A Narrative Review for Clinical Practice

Insect bite hypersensitivity (IBH) is a seasonally recurrent allergic dermatitis representing one of the most prevalent dermatological conditions in horses worldwide. This condition, driven by hypersensitivity to salivary allergens of Culicoides spp., causes substantial discomfort, welfare impairment, and potentially economic loss in equine populations. The pathogenesis of IBH is complex, involving genetic predisposition, epithelial barrier dysfunction, and a skewed T-helper 2 (Th2)-mediated immune response with elevated IgE production and eosinophilic inflammation. Advances in immunogenetics and molecular immunology have improved the understanding of the disease’s multifactorial nature. Research on immunotherapy and cytokine-targeted treatments is contributing to the development of more effective therapeutic options. This review synthesizes current knowledge on the immunopathogenesis and genetic determinants of IBH and discusses both conventional and emerging strategies for its clinical management.