Urticaria

(ur-tik-a’ ’-re-ah) [urtica, a nettle]. Nettle-rash, hives; a disease of the skin characterized by the* development of wheals, which give rise to sensations of burning and itching. They appear suddenly in large or small numbers, remain for from a few minutes to several hours, and disappear suddenly. The disease may be acute or chronic, and is due to agencies acting upon the vasomotor system, such as gastrointestinal disorders, the ingestion of certain foods, as shell-fish, strawberries, etc. U. bullosa, U. characterized by the formation of bullae. U. fact it i a, U., Factitious, der mog raphia, dermographism, the form produced in individuals with an irritable skin by any slight external irritation. U., Giant-, U. gigans. See U. oedema tosa. U. haemorrhagic a, purpura urticans, a variety characterized by hemorrhage into the wheals from. rupture of the extremely congested capillaries. U. medic a mentos a, U. from the use of certain drugs. U. oedema tosa, giant-urticaria, a variety characterized by the sudden appearance of large, soft, edematous swellings of the skin and subcutaneous ti ue, which may measure several inches in diameter. U. papulosa, lichen urticatus, a form occurring in children, in which, as a result of the inflammatory effusion, a small, solid papule remains after the subsidence of the wheal. U. pigmentosa, a rare type which begins within the first few months of life and consists of large, reddish, wheal-like tubercles that eventually change to a brownish-red or yellowish color. U. tuberosa, a form in which the wheals a ume a tuberous form and become very large, as big as a walnut, hen’s egg, or even larger. U. vesiculosa, U. characterized by the presence of vesicles. Urticarial, 647