Some people may have allergies to certain types of Christmas trees, such as fir or pine trees. These allergies are typically caused by the tiny particles that are released into the air when the tree is cut or when the needles are rubbed against the skin. These particles can cause symptoms such as sneezing, itching, watery eyes, and even respiratory issues in some people. If you suspect that you may have a Christmas tree allergy, it's best to avoid having a real tree in your home and opt for a fake one instead.