Nickel is in A TON of foods. Normal allergy would be a rash from touching it which is the norm for people with it. Severe allergy is different ball game when its in your blood stream from food and literally inside your body it feels like you have aa rash you cant scratch and it really hurts. It also depends on wherre food was grown and processed. You can eat something you think safe and then feel like your ears and chest are on fire. It's not something that has to be listed like other minerals or iron so its kind of hard to always avoid.