Ice cube test for cold urticaria

This series of photographs illustrates a positive ice cube test in a patient with cold urticaria. A plastic bag containing an ice cube and a small amount of water is applied to the volar aspect of the patient's forearm for 5 minutes and then removed. The area of application is observed and the response is recorded 10 minutes after removal. It is preferable to use a bag with ice and water rather than applying an ice cube directly to the skin, since some patients can sustain skin damage at temperatures below 0°C. Refer to the UpToDate topic on cold urticaria for further discussion of this test and its interpretation.