A Bull in a Pill Shop: Alpha-Gal Allergy Complicating Treatment Options for Postprocedural Hypothyroidism

Abstract

The galactose-alpha-1,3-galactose (alpha-gal) allergy, an IgE-mediated response to nonprimate meat, has a singular pathogenesis linked to tick bites and a delayed allergic presentation, which makes it especially cumbersome to diagnose and manage. As a large array of enteral medications contain ingredients derived from meat byproducts, this can affect the care of alpha-gal patients across multiple medical disciplines. Our objective is to present a patient with an alpha-gal allergy, which can complicate hypothyroidism treatment selection. In this case of difficulty tailoring thyroid replacement therapy secondary to the alpha-gal allergy, the diagnostic studies included IgE immunoassays for alpha-gal as well as thyroid function tests. A 45-year-old woman with postoperative hypothyroidism and a history of an alpha-gal allergy (diagnosed after an anaphylactic reaction to beef) could not be immediately started on any common thyroid hormone replacement formulation because of our concern regarding the possible presence of nonprimate mammalian meat byproduct components in the thyroid hormone medication. After consulting allergy and immunology specialists and compounding pharmacists and contacting multiple drug companies in an effort to confirm the nature of the inactive ingredients in their thyroid hormone products, she was prescribed a plant-based compounded levothyroxine preparation with good clinical results. This case emphasizes the importance of recognizing various risk factors and common drugs which may be associated with the alpha-gal allergy. It is not known how to best tailor enteral medications for patients with an alpha-gal allergy. Further research and pharmaceutical attention to this allergy are needed.