Q: Testing has confirmed that our 4-year-old is allergic to cashews and pistachios. (We visited an allergist after our daughter’s reaction to one cashew, in which her eye and lips became swollen and she got hives.) I’m unclear about what other foods she’ll need to avoid. While those are the only nuts she tested allergic to, I’ve read that cashews are in the sumac family, along with mangoes and peppercorns. Will she need to avoid those too?
Dr. Sicherer: There are individuals with allergy to cashew and pistachio who tolerate all other nuts. However, some families in this situation feel more comfortable avoidance of “all tree nuts”. This approach reduces the risk of cross-contact of safe with unsafe nuts or misidentification, and allows simpler instructions for children and caregivers.
Other families choose to permit specific nuts such as almond or hazelnut, which are easy to obtain without cross-contact, or they allow all types of contact with cashew/pistachio. This is a personal decision that should be discussed with your allergist.
You are correct that mango is in the same family as cashew and pistachio. Many foods share common ancestry or have similar proteins, but this does not necessarily translate to allergy.
Mango allergy is relatively uncommon and when it occurs it is not necessarily related to having a cashew allergy. Based on limited investigation, it seems that the mango pulp does not have proteins in common with cashew, while the mango seed, which is not eaten, does.
You also mention peppercorn. The issue here is not about black pepper or various fruits that include the term pepper (green, red, bell, chili, etc.) but specifically about pink peppercorns (also known as Brazilian Pepper, Rose Pepper, Christmas berry and others). Based on limited information, this ingredient may be a risk for people with cashew allergy. The dried berry may be used as a spice, although its use is not widespread.
Dr. Scott Sicherer is a practicing allergist, clinical researcher and professor of pediatrics. He is Director of the Jaffe Food Allergy Institute and Chief of Pediatric Allergy and Immunology at the Icahn School of Medicine at Mount Sinai in New York. He’s also the author of Food Allergies: A Complete Guide for Eating When Your Life Depends On It.