Sutton lists "foreign substances absorbed through the conjunctiva or respiratory tract"1 among the causes of urticaria. Brief summaries of three such cases of osmylogenic urticaria* seen by us may serve to call attention to this sometimes forgotten fact.
Case 1.—A 42-year-old white woman had suffered from ragweed hay fever for the previous six years. After the ragweed pollen had been in the air for a week or 10 days, urticarial wheals began to appear. These were first noticed as erythematous areas on the face, and later diffuse edema of the face and generalized hives became manifest. These hives persisted throughout the season, and, although they were present every year at this time, she was entirely free of them except at the ragweed season. This year she was adequately controlled for the first time by the usual preseasonal method and remained free of hives.
Case 2.—A white
DERBES VJ, KRAFCHUK JD. Osmylogenic Urticaria. AMA Arch Derm. 1957;76(1):103–104. doi:10.1001/archderm.1957.01550190107019