Tree nuts are generally cross-reactive. If one is allergic to a variety of nut, he or she should try to avoid all of them. The list of common tree nuts include almonds, Brazil nuts, cashews, hazelnuts (filberts), macadamia nuts, pecans, pine nuts, pistachios and walnuts. Peanuts are not included in this group, as they are not technically nuts (but, rather, legumes). Anyone with a nut allergy, however, should be cautious because they may be processed alongside actual nuts.