Diagnosis & management of alpha-gal syndrome: lessons from 2,500 patients

ABSTRACT

Introduction

Alpha-gal Syndrome (AGS) is a unique allergy to non-primate mammalian meat (and derived-products) that is associated with tick bites and is due to a specific IgE antibody to the oligosaccharide galactose-α-1,3-galactose (alpha-gal). AGS has many novel features that broaden the paradigm of food allergy, including that reactions are delayed 3–6 hours after exposure and patients have frequently tolerated red meat for many years prior to the development of allergic reactions. Due to the ubiquitous inclusion of mammal-derived materials in foods, medications, personal products and stabilizing compounds, full avoidance is difficult to achieve.

Areas covered

This review describes the author’s experience with diagnosis, management, and design of appropriate avoidance for patients with AGS and provides clinicians with practical advice for care of these patients.

Expert opinion

The number of patients with AGS is rising and may have exceeded awareness of the diagnosis amongst healthcare providers. In summarizing experience gained to thus far, we hope to create a resource for identifying and managing this unique allergic syndrome.

KEYWORDS:

• Alpha gal allergy
• food allergy
• anaphylaxis
• red meat
• IgE
• tick
• galactose

Article highlights

• Alpha-gal Syndrome (AGS) is an IgE-mediated allergy affecting an increasing number of patients worldwide

• AGS is characterized by delayed reactions after eating non-primate mammalian meat (e.g. beef, pork, lamb) or foods, medications, and personal products that contain mammal-derived ingredients

• AGS can be a challenging clinical diagnosis to make due to delayed reactions and guidance is provided for practicing clinicians to assist with recognizing and managing these patients

• Unique among food allergies, AGS is due to a carbohydrate-directed IgE response, can occur at any age, and appears to arise following a tick bite

• Patients often present with nighttime urticaria, angioedema, anaphylaxis, or even isolated gastrointestinal symptoms that are highly influenced by co-factors, including exercise & alcohol

• Owing to numerous ‘hidden’ alpha-gal exposures beyond red meats and the need for individualized guidance, we recommend co-management with dietician colleagues

Declaration of interest

The author declares research grants from NIH and CDC; a member of Genentech speaker’s bureau; has received royalties from UpToDate.

Reviewers disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Notes

1. Non-primate mammalian meat refers to meat derived from any mammal that is not a human or Great Ape. Commonly consumed examples are beef, pork, lamb, venison, rabbit, goat, squirrel, buffalo, etc. and include organ meats. For the purposes of this report, the term ‘mammalian meat’ and ‘mammalian-derived’ will be used to refer to non-primate mammalian meat and its animal sources as these are alpha-gal-containing foods or products. Equally, note that references may state ‘mammalian meat’ or ‘red meat’ yet these also refer to non-primate mammalian meat, which is the primary source of alpha-gal

Additional information

Funding

The author declares the following as sources of funding: U.S. Department of Health and Human Services; National Institutes of Health; National Institute of Allergy and Infectious Diseases; K08 AI085190; R01 AI135049