You hear nightmares occasionally that people were denied boarding because of their food allergies. Usually disclosing them while boarding, and not in advance. 

What do you do? Disclose well in advance, while boarding, or not at all? Anyone had any issues?

It really depends on the online allergy policy. If they have a clear policy I will disclose my allergies. If they have no policy, I wait to board and ask the flight attendant what they do for allergies (more out of curiosity). 

Until there is something clear and consistent it will always depend on what they say and how I feel. This all comes after almost being denied board twice from two different airlines. 

For now I take all the precautions I can by wearing long sleeves, a hood, wiping down my space, and carrying my medications. 

Hi Kortney, May I ask which airlines you were almost denied boarding after disclosing a food allergy? My daughter is allergic to tree nuts and we travel quite a bit.  We are lucky this has not happened to us before. It would be helpful to know which airlines we should try to avoid for her food allergy.  Thank you for your help!