Rosacea is increasingly being viewed as an immune-based disorder. Various immune factors, such as eicosanoids, proinflammatory cytokines, and polymorphonuclear leukocytes, appear to be involved in the vascular, inflammatory, and proliferative subtypes of this disorder. Many pharmacologic agents that effectively treat the symptoms of rosacea show anti-inflammatory and/or immunomodulating effects, providing further evidence that rosacea is an inflammatory disorder.