Hi, welcome to the forum, determination of the food you are allergic to, is one of the challenges which you need to pass through. The common existing food allergens are Peanut flour, peanut butter, powdered egg white etc. But in your case it is quite evident that you are allergic to pepper.
As allergic reactions are IgE mediated, blood tests will show increase in these levels secondary to a food allergy.
When such food is consumed in large quantities can elicit allergic reaction in the form of runny nose, hives, redness of skin, itching etc. You need to note down such food also in your diary and avoid the intake in future. For hypersensitivity reactions oral antihistamines and short course of nasal decongestants can be taken against prescription.
I suggest you to consult skin specialist/ immunologist for further line of management. Take care and regards.
I would keep a Food Diary and note what types of foods are causing a reaction. For example are you Gluten Intolerant?