Is it possible to be allergic to another person?

Is it possible for a person to be allergic to cold?

• I have a friend who always wears really warm clothes, even in the summer. Like, it's really hot and she'll be wearing a turtleneck! We asked her why she always wears winter clothes and she told us her doctor said she has a condition that makes her allergic to cold, and so she can never be cold. I've never heard of something like this. She said she wasn't joking and I've heard of cold intolerance, but that's not like what she said. Can a person really be allergic to cold?

• Answer:

  As strange as it sounds, it's possible to have an allergy to cold temperatures. Doctors refer to this as cold urticaria (ur-tih-KAR-ee-uh). It's also sometimes called cold allergy or cold hives. With cold urticaria, exposure to cold temperatures causes redness, itching, swelling and hives on your skin. As much as possible, people with cold urticaria should avoid exposure to cold air as well as cold water. For example, swimming in cold water is the most common cause of a severe, whole-body reaction — leading to fainting, shock and even death.