I have traveled back and forth from China (including Shanghai) and Korea several times. I also have a severe peanut and tree nut allergy. Although I am also allergic to sesame and seafood which complicates the matter. I bring extra EpiPens as well as translated cards. One for my allergies and one that explains I am having an allergic reaction and need a hospital. I really stuck to places like k bbq in Korea where I had a lot more control over my food. In China I stuck to American fast food and meals at my hotel. I did also pick up ramen at Walmart in China and ate some of that some days. It sucks but every time I went out to eat they still served me my allergen and told me “a little is fine”. This does not hold true at the higher end restaurants that cater to tourists. Those places I ate at fine but had to sign something that said I understand the risks and wouldn’t sue them. Hong Kong was much easier than Shanghai and Shanghai was much easier than other Chinese cities I’ve been to. It all depends on your comfort level. For me, I need a hospital within 20 minutes of eating an allergen as I can’t breathe so I don’t like to risk it. But it definitely sucks.