There are a number of seasonings common to pizza sauces and many Italian foods with red sauces. Many adults who have displayed no reaction in the past can develop what are called adult-onset allergies.
The first and most obvious cause could be tomatoes, which is where the sauces get their color. Also, many pizza sauces and red Italian sauces contain Oregano, Sweet Savory, Basil, and Marjoram. These herbs can cause allergic reactions in some individuals.
Try isolating the ingredients, and see if you react to them individually, before deciding to remove anything from your diet.
Check with your doctor about your symptoms - your doctor can recommend a treatment which will hopefully relieve your symptoms. Hope this helps.