CNN: Woman is allergic to cold
Diagram (mind map) of acute urticaria.
Diagram (mind map) of chronic urticaria.
Physical urticaria is defined as hives provoked by physical stimulus such as:
Cold urticaria due to cooling the skin
Dermographism due to stroking the skin
Cholinergic urticaria due to exercise, emotion, or heat
Solar urticaria due to sun exposure
Physical urticaria can be confirmed by challenge testing, and is best treated symptomatically by avoidance of provocative stimuli and antihistamines.
Physical urticaria does not respond to steroids since they do not inhibit mast cell degranulation. That is why steroid use is not a contraindication to skin prick testing. Epinephrine, which is used for both diagnostic and therapeutic purposes, inhibits mast cell degranulation.
There are several types of cold urticarias. Acquired (essential) cold urticaria can be deadly. For example, a swimmer with history of cold urticaria jumped into a cold water lake, developed urticaria and hypotension which lead to brain ischemia.
Testing procedures for diagnosis of physical urticarias depend on the cause (stimulus):
- Dermographism: Stroking with narrow object, e.g. a tongue depressor
- Cold urticaria: ice cube test
- Heat urticaria: test tube water at 44°C (111°F)
- Pressure urticaria: Sandbag test or a bag with heavy books (Middleton's Allergy textbook, 2 volumes)
- Vibratory urticaria: vibration with laboratory vortex for four minutes
- Cholinergic urticaria: exercise for 15-20 minutes or leg immersion in 44°C (111°F) bath
- Aquagenic urticaria: challenge with tap water at various temperatures
Urticaria: A Short Review
Mind Maps: Urticaria
Chronic Idiopathic Urticaria (Hives)
Autologous serum skin test in chronic idiopathic urticaria
The Ice Cube Test: Cold-Induced Urticaria. NEJM Images in Clinical Medicine, 02/2008.
Image: Cold-Induced Urticaria http://twitpic.com/e8lh2 - via @MatthewBowdish
Idiopathic Cold Urticaria. Consultant. Vol. 45 No. 13, November 1, 2005.
"Young mother must wrap up all year round because she is allergic to the cold" http://goo.gl/w25WB - Cold urticaria in Daily Mail.