Does being allergic to peanuts mean I’m also allergic to pecans?

Dear Reader,

This might be nuts, but peanuts aren’t really nuts! Peanuts are legumes, making them more like peas, lupin beans, soybeans, lentils, and chickpeas. Legumes are often identified by having a stem, leaves, and seeds that grow in pods. On the other hand, tree nuts grow on, well, trees. Some tree nuts include pecans, almonds, Brazil nuts, cashews, hazelnuts, pistachios, and walnuts. In terms of allergies, some people with peanut allergies might be allergic to pecans, but this isn’t always the case.

About one to two percent of people in the United States (US) have a peanut allergy, making it one of the most common food allergies. While most people with peanut allergies don’t have other allergies, it’s estimated that up to 30 percent of them are also allergic to tree nuts like pecans. Having eczema, or an egg or soy allergy could also increase your risk of having a peanut allergy. However, some individuals may outgrow their allergy, while others can develop a new allergy over time. Tree nut allergies are also common in the US but less so than peanut allergies. The wide variety of tree nuts may also mean that some people are allergic to only a few nuts, while others are allergic to all tree nuts. Some nuts are more closely related due to the proteins they contain, such as pecans and walnuts, or cashews and pistachios.  

There’s also the possibility of reactions to both peanuts and pecans, even if you're only allergic to one of them. Peanuts and pecans have overlapping protein families. This means that eating something with proteins that mimic those in the foods you’re allergic to might cause your body to react in the same way. Likewise, people with peanut allergies might be sensitive to foods like soybeans or lupin beans because they’re closely related to peanuts. For more information on sensitivities and allergies, consider checking out the Q&A about food sensitivity tests.

It’s also important to note that there is a difference between having a food allergy and food intolerance. If you’re curious about whether you’re also allergic or simply intolerant to pecans or other tree nuts, it’s best not to try them on your own, in case of a serious allergic reaction. Speaking with a health care provider or allergist could help you figure out if you’re able to eat pecans or not. To do this, they may give you an oral food challenge where you try foods under their supervision. Alternatively, they may do a skin prick test to see how your body reacts. Being cautious of cross-contamination of allergens when eating at unfamiliar places and checking the labels of processed and packaged foods can help you avoid consuming peanuts or traces of peanut protein.  

To pecan, or not to pecan, that is the question—and it’s a hard nut to crack!