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Removal of allergen in acute allergic reaction: Does it help?

Three Part Question

In [patients with acute allergic reaction] does [removal of allergen or sting] lead to [stopping further progression of reaction]?

Clinical Scenario

A 19 year hair dresser arrives to emergency department after colouring her own hair with a new type of dye. She has severe allergic reaction with urticaria and facial edema. You remember Britney and suggest to her that shaving all her hair may stop her progressing to further reaction. You wonder whether this will really work for her.

Search Strategy

Medline 1966- 03/2007
"((anaphyla$.MP.) OR (allerg$.MP.) OR (hypersensitivity)) AND ((remove) AND (allergen))"
LIMIT to humans and English language

Search Outcome

75 papers were found.
No paper was relevant to the original question.


Scadding K G had responded in the form of letter to the BMJ to Fisher M's article Treatment of anaphylaxis. BMJ 1995;311:731-3, wherein he reiterated that contact with the allergen should be prevented immediately. He suggested that in case of stings or intramuscular injections a tourniquet should be applied proximal to the site; bee stings removed, and any drugs being given intravenously at the time that the anaphylaxis occurred should be stopped. He even went on to suggest that vomiting should be induced in conscious patients. However he has not mentioned anything about gastric lavage for recently ingested food. It is believed that the cascade once started can not be prevented without pharmacological intervention or natural termination. There is finite number of mast cells and basophils to produce mediators in response to allergen. The role of removal of allergen is not clear, as multiphasic reactions do not necessarily occur in patients who have had meal wherein the allergen is still in the body. In bites and stings, many times, it is not possible to remove all the bites. Injection in gluteal or deltoid muscle can not be tournequeted.

Clinical Bottom Line

There are no studies to suggest that removal of allergen prevents further progression of allergic reaction. Further studies are required. Level of evidence is 5 and therefore grade of recommendation is D.