July 27, 2006

Q Is there such a thing as being allergic to cold? I think I am. When I go outdoors in the cold and then come back inside, I break out in hives. It doesn’t happen all the time, but it happens enough to make me wonder about it. What’s going on?

A Two body mechanisms are involved in the production of hives. Blood vessels close to the skin surface dilate and leak fluid, and that contributes to hive formation. In addition, mast cells, scattered in and beneath the skin, release histamine and other chemicals that promote the emergence of hives.

‘Urticaria’ is the medical name for hives. What you describe falls into a category of hives called physical urticarias. Among physical urticarias is dermatographism hives that form a line when the skin is stroked with a pencil or pen.

Another example is pressure urticaria –– hives that come when something presses on a part of the body. People with this kind of hives get them where the straps of a backpack weigh down on the skin. Another kind of hives is the urticaria that comes to some people when sunlight strikes them.

Cold exposure can also bring on an explosion of hives in sensitive people. Often the hives don’t appear until these people come in from the cold and begin to warm. You can test for cold urticaria by putting an ice cube on the forearm and leaving it there for four to 10 minutes. If you have cold urticaria, the place where the ice cube is laid will be blanched and then develop a swelling and redness.

Taking an antihistamine before going out into the cold can sometimes prevent this reaction. If it doesn’t, the combination of an antihistamine along with cimetidine might do so. Cimetidine is used for heartburn control. It does have properties similar to antihistamines and can work in concert with them.

Check with your doctor about this.

Q I have been seeing a doctor for back pain for more than two years. I have had innumerable X rays, scans and examinations. Nothing has been found. I would like to try acupuncture. Is it a hoax?

A Acupuncture has been practised for more than 2,500 years. Any medical treatment that lasts that long cannot be a hoax. There have been controlled, randomised trials to evaluate its effectiveness. Some of those trials give it a thumbs up. Millions of people have turned to it for relief of many problems, including back pain.

I must confess that my personal knowledge of acupuncture is sorely lacking. If you want to give it a try, there is no reason for you not to do so. You have had all sorts of tests and investigations, and nothing dangerous was found. The only suggestion I can make is to be sure your therapist comes recommended.

Q I developed a rash and a terrible itch on my wrist. The dermatologist says it’s lichen planus, and he gave me a cream for it. I have used it for a week, and it’s not working. What would you say to use for it?

A I say to wait longer than a week before you throw in the towel for your present treatment. Lichen planus is a fairly common skin condition with five features that begin with a P: purple colour; papules –– tiny bumps; planar –– the bumps have a flat surface; polygonal –– they’re many sided; and pruritus –– they itch like crazy.

Your cream must be a cortisone cream. That’s the standard treatment for lichen planus. One week is not enough time for it to work. If, in another week or two, there is no improvement, then contact the doctor. A change in the cream could turn things around, or a change to a more potent preparation might do the trick.

Are you taking an antihistamine? Antihistamines won’t do anything for the rash, but they can lessen the itch.

Dr Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write to him or request an order form of available health newsletters at P.O.Box 536475, Orlando, FL 32853 6475.

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