Relevance of patch testing in patients of chronic spontaneous urticaria and its correlation with serum IgE level

Abstract

Objectives: Chronic spontaneous urticaria (CSU) is defined as short lived (< 24h) wheals occurring spontaneously without any triggering factors, daily or almost daily for at least 6 weeks. Though CSU is mainly a Type 1 hypersensitivity reaction, earlier studies suggested contact allergy may have some role to play an important role in the etiopathogenesis of CSU. The objective of the study is to find out the relevance of patch test in the etiopathogenesis of and its correlation with serum IgE level. Materials and Methods: Thirty-one patients of CSU were thoroughly evaluated for clinical and laboratory parameters. We conducted patch testing with Indian Standard Series (ISS) in all of them and tried to find out the relevance of every positive reaction. Relevant positive cases were asked to avoid exposure for 2 months and were maintained only in breakthrough antihistamines. Furthermore, correlation of positive patch test reaction with high IgE and eosinophil count were studied. Results: Seventeen (55%) cases came positive for patch test. Potassium dichromate, lanolin, benzocaine, and fragrance mix were the most common offenders. Patients with very high IgE count had patch test positivity with multiple allergens. Seven of the fifteen patients who had relevant positive patch results could be followed up to remission; three were lost to follow-up. Conclusion: Patch test with ISS may give important clue to in a subset of patients of CSU and thus may be considered an important part of routine investigations of CSU.