My wife contracted Alpha-gal syndrome from a tick bite about 20 years ago. Causes an allergic reaction when eating meat from mammals. Symptoms would come on several hours after eating. She'd have hives and sever abdominal pain and said it felt like her throat was closing up. Allergy tests found nothing but at the time it's not something they tested for because the condition was still undiscovered. We figure out what was causing her reactions through trial an error. It was quite the challenge to figure out because I'm vegetarian so it was somewhat rare for her to eat meat unless we got something out of the house or she made something special for herself.