A 57 yr old man had had recurrent ulcerative lesions on his left hand for 2 yr. The ulcers were associated with chronic eczematous changes resulting from primary irritant contact dermatitis to sodium silicate, as indicated by positive patch tests. He used sodium silicate in a dyeing process in his work. He also had contact urticaria. An immediate wheal and flare reaction was found 15 min after application of sodium silicate to a scratch test site. This response was not seen in healthy control subjects.