Chronic Spontaneous Urticaria: An Etiopathogenic Study.

ABSTRACT

Importance Exact etiopathogenesis of chronic spontaneous urticaria (CSU) remains elusive. Infections, pseudoallergens, autoimmunity, and contact sensitization are various postulated factors. Few studies are available measuring cytokine levels in CSU. Objectives: The aim was to study various etiological factors of CSU and levels of IL-6 and IFN-ϒ in cases and controls, and correlation between various etiologies with the levels of the abovementioned interleukins in the cases. Design: Case-control study performed over 2 years with no follow-up of the participants. Setting: It was a referral-center-based study. Participants: Sixty patients of CSU and equal age and sex-matched healthy controls were recruited on the basis of convenience sampling. Exposures Biochemical and hematological investigations with hepatitis serology, thyroid function tests, anti-thyroid antibodies, and levels IL-6 and IFN-ϒ were performed in all cases and controls. All cases were subjected to ASST. Cases with all above negative tests were patch-tested with Indian standard series. Urticaria activity score (UAS7) was calculated for all the cases and repeated in patients with positive etiological factor after 3 weeks (improvement after allergen or drug avoidance, treatment of infection). Outcomes: To study the various etiological factors (food, infection, autoimmunity, autoreactivity, and contact sensitization) and the levels of IL-6 and IFN- γ in patients of chronic spontaneous urticaria. Results: Etiology was ascertained in 75% of patients (autoimmunity 50%, contact sensitization 21.67%, food and drug allergy 1.67% each). Mean values of the interleukins and anti-thyroid antibodies were significantly higher in cases versus controls. Levels of IFN-ϒ were significantly elevated in patients with higher UAS7 scores. Conclusion: Antithyroid antibodies, ASST, and patch testing are important tools and should be considered in patients of CSU after a thorough history and history-based workup. Elevated levels of IL-6 and IFN- ϒ in cases suggest that both Th1 and Th2 type of immune responses are implicated in pathogenesis of CSU.