Tick‐induced allergies: mammalian meat allergy and tick anaphylaxis

• Published in: Medical journal of Australia Vol. 208; no. 7; pp. 316 - 321
• Main Author: Nunen, Sheryl A
• Format: Journal Article
• Language: English
• Published: Australia 16-04-2018
• Subjects: Anaphylaxis - immunology; Anaphylaxis - parasitology; Animals; Food Hypersensitivity - immunology; Food Hypersensitivity - parasitology; Humans; Immune system diseases; Mammals; Meat; Tick-Borne Diseases - immunology; Wounds and injuries; Insect bites and stings; Anaphylaxis; Tick bites; Food hypersensitivity; Hypersensitivity
• ISSN: 0025-729X; 1326-5377
• DOI: 10.5694/mja17.00591

Summary

Mammalian meat allergy after tick bites and tick anaphylaxis are the most serious tick‐induced allergies. They are often severe, should be largely avoidable and offer fascinating insights into the development and prevention of allergies.
Australian clinicians reported the first cases of tick anaphylaxis and discovered the association between tick bites and the development of mammalian meat allergy. The subsequent finding of the allergen epitope within the meat responsible for the allergic reaction, α‐gal (galactose‐α‐1,3‐galactose), stimulated further interest in this emergent allergy.
Reports of mammalian meat allergy associated with bites from several tick species have now come from every continent where humans are bitten by ticks. The number of diagnosed patients has continued to rise.
Clinically, mammalian meat allergy and tick anaphylaxis present quite differently. The prominent role of cofactors in triggering episodes of mammalian meat allergy can make its diagnosis difficult.
Management of mammalian meat allergy is complicated by the manifold potential therapeutic implications due to the widespread distribution of the mammalian meat allergen, α‐gal. Exposures to α‐gal‐containing medications have proved lethal in a minority of people, and fatal tick anaphylaxis has been reported in Australia. Prevention of tick bites is prudent and practicable; killing the tick in situ is crucial to both primary and secondary prevention of allergic reactions.
Mechanisms in the development of mammalian meat allergy constitute a paradigm for how allergies might arise.