Just about anything can make you break out in hives: Foods such as peanuts or strawberries, drugs such as penicillin or aspirin, vitamin supple-ments, heat, cold, sunlight, exercise, fever, stress, and even scratching or rubbing the skin are among some of the possibilities.
Some substances actually cause an allergic reaction that can triggers hives, while others have absolutely nothing at all to do with allergies. Strawberries, for example, contain a chemical that can cause cells in your body to release histamine, a chemical also produced in allergies, which allows blood plasma to leak into the skin and form the hives, explains Philip C. Anderson, M.D., chairman of dermatology at the University of MissouriColumbia School of Medicine.
And sometimes only a tiny amount of the culprit is needed to set off a reaction. You can be sensitive to fish and order something completely different in a restaurant. But its cooked in a pan that was previously used to fry fish, and you break out in hives, explains Larry Borish, M.D., staff physician at National Jewish Center for Immu-nology and Respiratory Medicine in Denver.
Dont confuse hives with other skin eruptions. Hives (or urticaria) occur when blood plasma leaks into the skin, causing wheals or swollen areas. They can be as small as a pencil eraser or as large as a dinner plate, and they usually last only a few hours. But new hives may form continuously. And as they form, they often itch.
An attack of hives generally lasts a short time, often just a few days. (Some people, however, may be plagued with recurrent outbreaks or with hives that persist for years.) Here are some tips for relief.

Take an oral antihistamine.
The most recom-mended remedy is over-the-counter Benadryl but it may cause drowsiness. That may not be so bad, since hives are generally worse at night, and the itch is more annoying then, says Borish.

Dont scratch.
Its said that with hives, a million scratches are never enough and one is too many, says Borish. Scratching can increase local inflammation and even cause more hives.

Wear gloves to bed.
If you think youll scratch in your sleep, gloves will help prevent damage.

Wrap up the affected area.
Wrap an elastic bandage around the area with hives or cover it with clothing so you cant reach it with your fingernails.

Use a milk compress.
Wet a cloth with cold milk and lay it on the affected area for 10 to 15 minutes at a time. Dont freeze the skin, warns Judy Jordan, M.D., a dermatologist in San Antonio and a spokesperson for the American Academy of Dermatology. Just cool it.

Chill the itch.
Hold an ice pack or ice cubes in a thin towel on the skin for five minutes at a time, three to four times a day.

Take a bath.
Put half a box of baking soda or one cup of oatmeal in the water first, says Jordan.

Try cortisone.
A one percent cortisone preparation, available without a prescription, may help.

Try to ferret out the cause.
In the overwhelming number of patients, theres no explanation found, says Borish. We only find the cause 20 to 30 percent of the time. Do remember that hives generally show up within half an hour of eating. You dont get hives the next day from something you ate the night before, he says.

Avoid the trigger.
This ones pretty obvious, but if you know that cold sets off hives, dont put your hands in the freezer. In fact, jumping into cold water could be life-threatening, points out Borish. And theres no question, he says, that if youre prone to hives, stress will trigger them.

Treat the underlying infection.
If hives turn into a chronic problem, they may be due to an infection. You can have a tooth or yeast infection and not be aware of it, points out Jordan. Consider these possibilities and have them checked out.

Relieve the pressure.
Hives often form where clothing is tight, such as under bra straps or waistbands.

Use a moisturizer.
If dry skin contributes to the itch, apply a moisturizer to relieve it.

Dont make the problem worse.
Nonprescription anti-itch lotions or creams can cause allergic reactions. If you react to topical Benadryl and topical products ending in -caine, youll be in worse shape after using them. Calamine lotion, that old standby for so many itches, doesnt do much for hives either.