Misdiagnosis of alpha-gal syndrome as non-celiac gluten sensitivity or lactose intolerance: A diagnostic blind spot for clinicians

Table 2 Comparison between alpha-gal syndrome, non-celiac gluten sensitivity and Lactose Intolerance based on their diagnostic and pathophysiologic mechanisms

	AGS	NCGS	Lactose intolerance
Etiology	Mammalian products including beef, pork, lamb, venison and sometimes dairy/gelatin	Symptoms are triggered by gluten	Digestive problem caused by deficiency of the lactase enzyme
Onset	Delayed (typically 2-6 hours after eating the trigger food)	Within hours after consuming gluten	Within hours after dairy ingestion
Symptom manifestation	Hives, itching, swelling, nausea, vomiting, abdominal pain and diarrhea. Can potentially manifest as anaphylaxis	Abdominal pain, bloating, diarrhea, fatigue and headache	Nausea, bloating, abdominal cramps, gas and diarrhea
Immune mechanism	Allergic (type 1 hypersensitivity reaction)	Innate immune system	Digestive disorder involving lack of lactase enzyme
Diagnosis	Blood test for alpha-gal-specific IgE antibodies	Clinical diagnosis made by excluding celiac disease and wheat allergy but involving a positive response to gluten-free diet	Hydrogen Breath test and Lactose intolerance test

NCGS: Non-celiac gluten sensitivity; AGS: Alpha-gal syndrome.