The questions of why allergies exist and why they are becoming more prevalent continue to puzzle immunologists. Recent research has uncovered a wealth of details and in the process grown an impenetrable hedge of acronyms around the issue, but the answers may be hidden elsewhere, in the ecology and evolution of our interactions with insects, worms and snakes. Michael Gross reports.

Two theories provided:

  • Hygiene hypothesis to explain how allergy goes widespread
    In industrialized areas, higher cleanliness may induce hypersensitivity to allergens. A study reveals that interactions between parasyte worms, commensal bacteria and immune system could give explanation of how the hypothesis works.

  • Toxin hypothesis to explain how allergy arises in the first place
    Allergy is an evolutionary result of combating natural toxins.