People with tree nut allergies tend to suffer from them for their entire life. About 91 percent of children allergic to tree nuts never overcome their allergy [source: FAI]. Besides digestive problems, allergic reactions include asthma, hives, atopic dermatitis and anaphylactic shock.
Among the wide variety of tree nuts, the most common offenders include cashews, walnuts and almonds. Uncommon tree nuts, like kola and shea nuts, are less likely to lead to allergic reactions [source: Brostoff]. However, because people are rarely allergic to just one kind of tree nut, some experts advise steering clear of all nuts if you've got a known allergy to any type of tree nut [source: FAI].
What's more, you may experience an allergic reaction to tree nuts even if you don't ingest them. Merely touching or using a topical product that contains them can be dangerous. Scan the ingredients lists in lotions and shampoos, many of which include tree nuts in their formulas.