Urticaria is a localized or diffuse rash, which is manifested by redness, itching and raised wheals (erythematous, roundish or irregular lesions, of variable size); it can be acute (temporary) or chronic (lasting or recurrent).
In pathogenesis, a massive release of histamine is recognized through mast cells (cellular elements that play an important role in the immune system), which results in an inflammatory reaction.
The term " hives " comes from the Latin name Urtica, as the symptoms that characterize the disorder recall the cutaneous manifestations that appear after coming into contact with the nettles .
The leaves of these plants have, in fact, a substance with a revulsive action, which is irritating to the skin of men and animals. The result of a possible contact with the thin stinging trichomes (similar to hairs) that cover the leaf blades and the stem of the nettle leads to the formation of small erythemas on the skin, associated with a feeling of intense itching and numbness.
