We'd be missing the mark with this list if we didn't include the obvious: Some foods that trigger allergic reactions when you ingest them can also cause harm when applied to the skin. Sure, it sounds simple enough, but it's easy to overlook. Take soy, for example, which causes some people to get food allergy symptoms like itchy, irritated skin. A similar reaction can occur when a skin moisturizing product that contains soy is applied directly to the skin. Itchy red and bumpy skin will signal that your body doesn't tolerate soy, even if it just makes external contact.
Eggs, milk, peanuts and wheat are a few other things that cause food or skin allergies with some people. If you know you're allergic to a food that we haven't mentioned, you'll want to pay attention to whether it's in the moisturizer you use. Keep this skin moisturizing tip in mind: If you ever develop a skin allergy, you may want to switch to a moisturizer that doesn't contain the ingredient you already know causes you a food allergy.