Some people break out in hives when they dash in and out of an air-conditioned store in summer. Or when they come into a warm house after shoveling snow. Or if they take a quick dip in a chilly pond or pool. Or even if they rinse their hands in cold water.
That’s called cold urticaria, and while it’s the drop in temperature that triggers the reaction, the symptoms appear as the body temperature warms up again. That increase in body temperature, it’s believed, releases histamine and other allergy-triggering body substances. Hives may develop all over the body, but they’re usually more prominent in the areas directly affected by the cold, such as uncovered hands or face. If very cold food is eaten, the lips and tongue may swell somewhat. And cold-induced hives may be accompanied by headache, vomiting, rapid heartbeat and fainting.
Cold urticaria is related to allergy to exercise, which also prompts a rise in body temperature, and is medically referred to as a ‘cholinergic’ allergy, which means that the allergy involves the nervous system. And cold allergy can be accompanied by water allergy, a rare and slightly different variation of cholinergic allergy.
It’s not always easy to tell the difference between cold urticaria, exercise urticaria or water urticaria. Widespread hives that develop after swimming, for example, could be caused by cold water, exertion (if it’s a heated pool) or by the water itself. To sort it out, doctors do what amounts to a patch test with an ice cube. If you don’t react, you’re not cold sensitive.
Allergy to cold temperature is very often part of one of a few other, underlying illnesses, and disappears when the disease is cured. In other cases, cold allergy simply subsides as mysteriously as it began. If not, common sense tells the individual to take precautions against exposure to cold. Where cold is unavoidable or the allergy is a major problem, many people have been successfully desensitized to cold temperature by gradual exposure to decreasing temperatures – either in a cold room or cold water – for progressively longer periods of time until cold can be tolerated.
If that doesn’t work, antihistamines may help. While we don’t encourage casual use of drugs, we do feel that in certain circumstances – such as this – medication is less of a hazard than the risk of a severe reaction to an unavoidable allergen.
‘Allergy to exercise’ may sound like a lame excuse to stay chair-bound. But there actually are a few rare individuals who swell up and break out in hives after even mild exertion. A couple of laps across the pool or a few minutes of jogging leave them not only red and itchy, but possibly even dizzy, nauseated and exhausted. In most cases, antihistamines can help.
Asthma attacks, too, may be triggered by strenuous exertion. But those breathing difficulties may be due to the direct effect of cold, dry air on sensitive airways and are in no way related to exercise-induced hives.