Ask The Expert
August 12, 2013
Food Intolerance and Chronic Urticaria
I am an allergist in Australia where low food-chemical diets are often tried in chronic urticaria. Many academic publications from the USA state that such diets have a limited role in this condition. These diets are often used in Europe, where they are often called 'pseudo-allergen diets'. Are there any RCT studies on this intervention? Can you advise on this diet's role in chronic urticaria?
In patients with chronic urticaria, an etiologic role for foods and food additives is frequently suspected, but rarely confirmed.
The possibility has been proposed that substances in foods, termed “pseudoallergens” – such as artificial preservatives and dyes in processed foods, or aromatic compounds in natural foods, may be a cause and/or an exacerbating factor for chronic urticaria.
The evidence supporting a role for a pseudoallergen-free diet in chronic urticaria has been evaluated in uncontrolled studies. In one such study (1), of 140 subjects, there were 48 “strong responders”, 19 “partial responders”, and 9 described as “natural coping subjects”; 92 (64%) did not respond. The authors concluded: “the pseudoallergen free diet is beneficial for one in three patients…”, and recommended a trial of this diet “as one of the first diagnostic procedures any physician recommends to every new chronic spontaneous urticaria patient who does not resolve spontaneously.” Another study (2) concluded that adherence to a stringently controlled pseudoallergen free diet is of benefit for “the majority of patients with chronic urticaria”, as 73% of the 64 chronic urticaria subjects enrolled in an uncontrolled study and placed on the diet experienced either evanescence or a significant reduction of symptoms within two weeks; however, only 19% of these 64 subjects exhibited symptoms in association with subsequent exposure to individual pseudoallergens upon oral provocation challenge.
In summary, the evidence is weak that pseudoallergen-free diets lead to improvement in the course of chronic urticaria. Based upon the burden associated with adherence to such a diet, until this intervention is shown to be of benefit in randomized controlled trials, pseudoallergen free diets cannot be recommended as an intervention for patients with chronic urticaria.
1. Magerl M, Pisarevskaja D, Scheufele R, Zuberbier T, Maurer M. Effects of a pseudoallergen free diet on chronic spontaneous urticaria: a prospective trial. Allergy 2010; 65: 78-83.
2. Zuberbier T, Chantraine-Hess S, Hartmann K, Czarnetzki B. Pseudoallergen free dit in the treatment of chronic urticaria. A prospective study. Acta Derm Venereol 1995; 75: 484-7.
David Lang, MD
Cleveland Clinic – Cleveland, Ohio, USA
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