Contact urticaria syndrome cus encompasses immediate contact inflammatory reactions that appear within minutes after contact with a substance what you should be alert for in the history contact urticaria refers to a wheal and flare reaction and or eczema following external contact with a substance usually appearing within 30 minutes and clearing completely within hours typically without residual signs. Contact urticaria also called contact urticaria syndrome is an immediate but transient localized swelling and redness that occurs on the skin after direct contact with an offending substance 1 contact urticaria occurs within 10 to 60 minutes at the site of contact of the offending agent and completely resolves within 24 hours 2 . What is contact urticaria contact urticaria is an immediate but transient localised swelling and redness that occurs on the skin after direct contact with an offending substance contact urticaria should be distinguished from contact dermatitis where a dermatitis reaction develops hours to days after contact with the offending agent. Contact urticaria is an immediate but transient localized swelling and redness that occurs on the skin after direct contact with an offending substance