Auckland Allergy Clinic ? WHAT?S NEW December 2007

Welcome to the Auckland Allergy Clinic web site. This section will bring you the latest breaking news in Allergy & Clinical Immunology and also additions we have made to the Clinic in the last month.

The Allergy News information provided on this web site is reviewed and approved by the Allergists at the Auckland Allergy Clinic. The information is sourced from International Medical Journals and Newspapers. These articles are chosen either because they are thought to be particularly good studies, very interesting Allergy News or relevant to New Zealand. The articles may not necessarily be the views of the editor. Where relevant the editor will add his/her comments at the bottom of the review.

These updates are provided for educational, communication and information purposes only.

Previous Newsletters:

May 2007

December 2006
April 2006
February 2006
May 2005

October 2004
August 2004
March 2004
January 2004

Oral (Provocation) Challenges

Vincent St Aubyn Crump ? December 2007

An allergy diagnosis is made by a very careful history, skin prick tests, blood tests (Immuno-CAP RAST), Patch tests, Atopy Patch test & Oral Challenges. A Double-Blind Placebo-Controlled (DBPC) Oral food Challenge is considered the ?gold standard? in the diagnosis of food allergies and some drug allergies.

The importance of taking a careful (thorough) history cannot be stressed enough, because not only can a good history give the diagnosis on its own, but it guides the Allergist towards stream-lined allergy testing. Random (battery) testing is financially wasteful and also time consuming and potentially misleading. The allergy tests should only be used to confirm a diagnosis that has been made based on the history.

The aim of oral food challenge is to study the consequences of food ingestion in an objective way. It is well known that the perceived prevalence of food allergies is much higher than the true prevalence, and this is due to the subjective symptoms that are often associated with food ingestion. This is due to a conditioned (Pavlovian) Response.

Clinical uses of oral challenges

To confirm a diagnosis of food allergy based on history and equivocal skin prick tests & / or Immuno-CAP RAST-type tests. The new Immuno-CAP tests are so sensitive & specific for diagnosing food allergies to milk, egg, peanut, fish, and wheat that oral challenges to these foods are very rarely done to diagnose allergy.

To diagnose Food Intolerance, where skin tests & blood tests are expected to be negative (not useful).

To see if a child has grown out of a food allergy, especially when the Immuno-CAP tests are equivocal.

To re-assure patients who, would otherwise be unconvinced that their symptoms are not attributable to the foods that they have developed a conditioned response to.

To confirm drug allergies.