Allergies to coconuts and coconut oil are considered rare. They can take two forms: a food allergy or a contact allergy. A tree nut allergy isn't necessarily related to a coconut allergy. Chances are higher of developing an allergy to touching things that contain coconut oil than developing an allergy to eating things with coconut oil in them. In both cases, your body is reacting to certain proteins it thinks are harmful. Your immune system responds by releasing an antibody called immunoglobulin E, and it tries to fight off the "dangerous" coconut invaders.
When it comes to a food allergy to coconut oil, your likely symptoms are itching, hives, nausea, vomiting, diarrhea, trouble breathing and swelling in your lips and tongue. A contact allergy to coconut oil -- which is often found in moisturizers, shampoo and other cosmetics -- can result in an itchy rash or blisters that develop within a day or two of touching the allergen.