The skin reaction that you describe certainly seems to fall in the strange class of 'urticarial' reactions. This has the chief features of developing fairly suddenly, with swelling in the skin (blotches, wheals or 'hives') and colour variations from normal to pink or white. Usually there is accompanying irritation, and sometimes crops of lesions may appear.

This is the body's defence mechanism of releasing 'histamine' chemical into the skin and deeper tissues in response to some form of allergen or irritant. The biggest problem is trying to determine just what this trigger is: it can be anything from certain foods to contact with various household chemicals; even temperature changes can be the cause. In females, hormone level changes may also be the cause.

There are various means of investigating possible allergic causes, usually carried out in a hospital dermatological department; this can be 'patch' testing or a series of skin tests. Elimination diets are always extremely difficult to organize, and the results are often unrewarding. Prevention is difficult until the causative agent is found, but there are some very good over-the-counter antihistamines available. Even one a day for a time can often keep the problem under control. Avoid antihistamine creams as they can cause some people to have skin irritations.

Keeping the skin cool will help to lessen the amount of histamine release. A solution of bicarbonate of soda is also a very safe and useful home remedy. Your condition will certainly need to be investigated if the problem persists. Fortunately, the tendency to develop urticaria often disappears in time without treatment.