Question: Can chocolate and cocoa powder cause eczema?

Answer: Yes. They are both relatively high in nickel and can cause allergic contact dermatitis in people who are nickel-sensitive or have a nickel allergy. (If you are allergic to milk, also be aware that even some dark chocolates contain milk). Just one serving of dark chocolate, for example, contained about as much nickel as an adult gets per day from all other foods and beverages combined.