Chronic spontaneous urticaria is defined as spontaneous wheal or angioedema that occurs repeatedly for more than 8 weeks and occurs at least twice a week.

The most accurate description of the wheal is ( ) A: these are palpable and elevated lesions more than 1cm in size. B: these are transient, well demarcated and elevated swellings of the<br/>skin. C: these are sharply circumscribed, elevated, clear fluid-containing<br/>cavities less than 1cm in diameter. D: this is simply a flat circumscribed change in the color or texture of<br/>the skin, without elevation or depression.