Avoid areas like parks or fields, particularly in the early evening when there is a lot of pollen at ground level. Get someone else to mow the grass. The only way to avoid perennial allergic rhinitis is to avoid the allergen that causes it. Urticaria Urticaria is an allergic skin rash sometimes called nettle rash or hives. Acute urticaria is caused by an allergen and can last anything from several hours to several days.
Chronic urticaria lasts for several weeks, months or even longer.
The cause of chronic urticaria is uncertain. It may be triggered in some people by certain infections, certain drugs or stress. An urticaria rash is pimply and very itchy, and can appear anywhere on the body. If your urticaria does not disappear after a week or two, or does not respond to antihistamine creams, or is accompanied by any other health problem, you should go back to your doctor.