Allergies are known to cause inflammation and create toxins in the system that are not good for overall brain health - and that's when someone has a brain that is not injured, so I believe that an injured brain is even more sensitive to the effects of allergies. That's why it's so important to keep allergies at bay.

I have had bad allergies and asthma my whole life. After the injury I sustained I was suddenly allergic to wheat and sesame seeds. It's important for me (and everyone else recovering from a brain injury) to stay away from things that cause systemic allergic reactions in them. At the very least, allergens are just another stimulus to overtax the brain and we don't need to deal with that.