When should the diagnosis 'contact urticaria' be used?

In the dermatological literature, the term 'contact urticaria syndrome' is often used with patients presenting no symptoms of contact urticaria, but symptoms of adjacent mucous membranes evolving to a systemic allergic reaction. Contact urticaria refers to a wheal and flare reaction following external contact with a causative substance. Its use should be restricted to skin: a skin reaction after direct skin contact.