Archive for February 4th, 2007

Cold-Induced Urticaria

February 4, 2007

There was a recent comment regarding a rash that occurred when a person went into cold water up to their knees that rapidly evolved into full-blown anaphylaxis.  So, it seemed appropriate to take a moment and explain exactly what happened.

There are individuals who are literally allergic to the cold. It happens more commonly from exposure to cold water, but  it can  be caused by cold air.  A close friend and athlete decided to go out for a short run one cold day, when it was about -10 degrees F.   After a short jog he began to develop shortness of breath and tightness in his chest.  He also began to break out with a red, itchy rash on his face.  Fortunately for him, he was right next to the hospital ER, so he intelligently ran in.  He was quickly diagnosed and treated for cold-induced anaphylaxis that required IV Benadryl and epinephrine.

For some strange reason, in these people cold exposure causes their mast cells to degranulate.  This produces an overdose of histamine, which results in vasodilation, hypotension, tachycardia, and bronchoconstriction, causing the symptoms of the rash (urticaria), shortness of breath, wheezing, tightness in the chest, and eventually a loss of their airway.

Symptoms of anaphylaxis, regardless of the cause:
Rash – red, raised, itchy welts (urticaria)
Dyspnea – wheezing – stridor that can rapidly deteriorate into extreme difficulty breathing and airway obstruction from the bronchoconstriction.

Treatment of Anaphylaxis:
Antihistamine: such as Benadryl (diphenhydramine) 50mg po
If they develop difficulty breathing:Epinephrine 1:1000, 0.3cc IM, that comes in a pre-filled syringe, EpiPen
Oxygen 15lpm by non rebreather, if available
Evacuation to the closest ER

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