Macadamia Nuts are "tree nuts". You may want to do some searches using those key words. Here is an excerpt I found from a website that is most helpful:
Cross-Reactivity Among Tree Nuts:
Most people with tree nut allergies are not allergic to all tree nuts. However, there is high cross-reactivity among various families of tree nuts. About 12 percent of people who are allergic to one tree nut are allergic to another tree nut. The strongest probability of cross-reactivity is between walnut and pecan, and between cashew and pistachio; however, many tree nuts have some possibility of cross-reaction between each other. For this reason, people who are allergic to one type of tree nut are generally advised to avoid all tree nuts as a precaution.
Cross-Reactivity Between Tree Nuts and Peanuts:
Peanuts are legumes, and are biologically unrelated to tree nuts. However, there is a high level of allergic cross-reactivity between peanuts and tree nuts, meaning that people with tree nut allergies are at increased risk of developing peanut allergies. If you are diagnosed with a tree nut allergy, your allergist will advise you whether to avoid peanuts as well.