Evolutionary origins and modern rise of allergic diseases: an integrative framework

Allergic diseases have become increasingly prevalent in recent decades, prompting significant research into their evolutionary origins and the mechanisms that drive these immune responses. A range of evolutionary models has been developed to account for both the emergence and modern rise of allergic conditions. The main explanations encompass parasite defense, reduced microbial exposure and hygiene-related factors, mechanisms of tissue damage detection, and immune surveillance acting as an early warning system. Explaining why the immune system reacts inappropriately to harmless antigens demands an evolutionary lens: one that integrates ancestral adaptive roles with present-day environmental shifts. Rather than proposing a new evolutionary theory, this narrative review synthesizes competing and complementary evolutionary explanations for allergic type 1 hypersensitivity, IgE-mediated disease within a unified immunological framework, thus emphasizing recent advances in epithelial biology, immune surveillance, and type 2 inflammation that have emerged over the last decade.