Dictionary.net

A vascular reaction of the skin characterized by erythema and wheal formation due to localized increase of vascular permeability. The causative mechanism may be allergy, infection, or stress.

Nettle-rash; inflammation of skin with lesiom.

Nettle-rash or hives; a skin-disease marked by transient eruption of wheals.

Hives, nettle rash; an acute or chronic affection of the skin characterized by an eruption of red, elevated, rounded efflorescences of irregular shape and size, which at a certain stage of their development appear blanched in the center and erythematous at the periphery, being then commonly known as wheals. The eruption is attended with intense itching. It is usually transitory, though sometimes disposed to recur.