physical urticaria
Last reviewed 01/2018
Types:
- dermographism - seen in 3-5% of the population
- dermatographism - minor trauma
- pressure - eg. on buttocks or soles. The swelling may be delayed for several hours, and usually persists for 1-2 days
- temperature: - cold - due to ice; cryoglobulins eg. in lupus erythematous; immersion in water. Tolerance may be induced by taking regular cold showers. - heat - eg. hot water
- solar - due to ultraviolet exposure
- aquagenic - due to contact with water irrespective of it's temperature
- cholinergic - exercise, emotion
- delayed pressure - jogging, sitting, lying, tight clothing
- cold - swimming in cold water, cold wind
- exercise - physical exertion
- solar - sunshine
- vibratory - use of vibrating tools
Investigations:
- challenge testing with appropriate stimuli e.g. ice-cube, exercise, etc.; cryoglobulins
Many patients have a physical element to their urticaria with triggering by heat, cold, pressure, vibration, water, ultraviolet light, etc. The physical urticarias are triggered reproducibly after a specific physical stimulus is applied . Weals usually appear immediately and often last for <2 h. A few patients have delayed-pressure urticaria, which as the name implies, comes on slowly after pressure, and lasts several hours or days. The physical urticarias can be more resistant to therapy and follow a protracted course
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