ANSWER: You have cold urticaria. “Urticaria” is the precise term for hives or wheals. Cold air can do it, but so can cold objects. Metal objects are more likely to do so because metal conducts heat away from your body faster. Swimming is the most dangerous activity for people with cold urticaria, and it shouldn’t be done in cold water.
Nobody really understands why cold urticaria happens. Avoiding cold and keeping the body covered up and warm are obvious and effective remedies. Antihistamines, such as Benadryl or Claritin, may help if you must be exposed to the cold.
DEAR DR. ROACH: Could you give me some information about BCG? If this were recommended to you as a treatment, would you hesitate to take it? — M.P.
ANSWER: Bacille Calmette-Guerin (BCG) is a weakened form of a bacteria related to tuberculosis. It is used in many countries as a vaccine against tuberculosis; however, its effectiveness at preventing TB is questioned.
BCG in North America is mostly used as a treatment for superficial bladder cancer. It seems to stimulate the immune system to fight off the cancer on its own, but it’s not clear exactly how it works. Serious side effects are uncommon, but it frequently causes bladder symptoms, which wear off usually within 48 hours.
I would hesitate before using it, but I would take it if my urologist felt it was my best option.