I have had allergies all my life, mostly sinus type reactions and I also have had asthma all my life. The asthma and the allergies are controlled with medications, and my pulmonary doctor started having me do the nasal flushes twice a day. Since I have been doing this the sinus infections have been reduced by at least 50%. Allergy testing showed that I was allergic to almost everything. I know what triggers these and I can take my medication in advance if I know that I will be around any of the triggers. One example is movie theaters, they are full of dust just look at the walls when the lights go up, so if I want to see a movie I take my medication before I go.
I have a seafood allergy, not just shellfish, I have been hospitalized 3 times with severe hives and in acute respiratory distress. I have an Epipen that I carry with me all the time. This past summer I developed and allergy to peanuts, same type of reaction as I have with seafood. I have learned to read the ingredients on all food and to ask questions at restaurants, do use MSG, do they cook with peanut oil, do they cook fries in oil that they have cooked seafood in, etc and if I am not sure I don't take the chance it is too risky. After a while it becomes second nature and I have learned how to do it without making a big deal, most places are very happy to help you, it is bad PR to have a customer collapse in the middle of dinner.
Good luck and your doctor is right about recommending bed covers.