J Med Assoc Thai 2015; 98 (12):1162

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Original ArticleOpen Access
The Effect of Food Avoidance in Adult Patients with Chronic Idiopathic Urticaria
Thaiwat S Mail, Nakakes A , Sangasapaviliya A

Background: Recent findings show food allergy is rarely the cause of chronic urticaria. However, reports showed up to 5% of chronic idiopathic urticaria (CIU) was food induced urticaria (FIU) and the remission rate with food avoidance in CIU was varied. According to recent studies, skin prick test (SPT) is not a gold standard for investigating the culprit food allergen in CIU. The clinical response for food avoidance is still unclear.

Objective: The purpose of the present study is to investigate the association of food allergen and SPT, the clinical response after positive food avoidance in adult Thai patients with CIU.

Material and Method: We conducted a prospective study that included 76 patients, who presented with CIU at the Division of Dermatology, Department of Medicine, Phramongkutklao Hospital, between September 1, 2009 and May 31, 2010. Personal data, general physical examination, and detailed history were obtained. Twenty food allergens were used to perform SPT at the allergy clinic. The positive food allergens were enrolled to avoid the culprit food allergens for two to four weeks and evaluated the clinical response.

Results: Fifty-one of 76 patients (67.1%) gave history compatible with FIU. Shrimp (54.9%) and fish (49.0%) were the two most commonly suspected allergens by the patients. Fifteen of 76 patients (19.7%) had positive SPT. In comparison to the SPT negative group in terms of clinical severity and effect on their daily lives, there was no significant difference. We then matched the SPT results with the patient’s history. Five of 76 (6.6%) patients had results of SPT matching the patients’ history. The five allergens in these patients were fish, milk, tomato, shrimp, and yeast. Fifty-one of 76 (67.1%) patients had negative SPT results but the patients suspected that certain foods were the cause of their urticaria. Fifteen of 76 (19.7%) patients had positive SPT results but the patients had never suspected any food allergen. Among these SPT positive patients, 13 food allergens were the culprits, the first three most common SPT allergens in this group were peanut, oyster, and tomato. Upon SPT positive food avoidance, 12 of 15 (80%) SPT+ patients had significant improvement of symptom score in term of clinical severity and effect on their daily lives.

Conclusion: Although SPT still yielded a low sensitivity for the diagnosis of FIU, the present study showed a very good response by food avoidance in patients who were SPT positive.

Keywords: Chronic idiopathic urticarial (CIU), Food induced urticarial (FIU), Skin prick test (SPT), Food avoidance


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