August 31, 2020
Dietary Modifications for Chronic Urticaria
Question
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 use in Europe, where they often called “pseudo-allergen diets”- are there any RCT studies on this intervention? Can you advise on this diet´s role in chronic urticaria?
Answer
The efficacy of dietary modifications to alleviate chronic spontaneous urticaria (CSU) is controversial. To my best knowledge, there are no systematic reviews and meta-analysis of double-blind, placebo-controlled, randomized clinical trials englobing a sufficient population to provide meaningful conclusions. Nevertheless, some lower-evidence studies performed worldwide propose significant benefit of particular diets in patients with chronic hives and wheals.
Suggested dietary modifications for subjects with CSU include pseudo-allergen-free (e.g., food additives), low-histamine, gluten-free, and specific-food-free (e.g., fish) diets.
Food additives can be recognized as antigens by the immune system, leading to the exacerbation of inflammatory symptoms, not only in patients with CSU, but also eosinophilic esophagitis, bronchial asthma, atopic dermatitis, and anaphylaxis. Clinical history and food challenges are essential to recognize sensitization to food additives.
Histamine generates itch, wheals and hives. Low-histamine diets could lead to reduced plasma histamine levels and diminished symptoms in subjects with CSU, especially those patients with extra-cutaneous histamine-mediated inflammatory symptoms (e.g., diarrhea, headache). It is mandatory to first exclude other inflammatory diseases.
On the other hand, unnecessary dietary restrictions might have a detrimental effect on the nutritional condition and quality of life of patients with CSU.
In summary, I recommend a thorough clinical history and, if necessary, personalized food challenges to stablish the relevance of ingested molecules in each individual with CSU. This approach can lead to the suggestion of a particular diet in some patients.
References
Paula Mazuelos-Weyrauch, MD
Allergy and Clinical Immunology
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