Chronic inducible urticaria: A systematic review of treatment options

Background Chronic inducible urticaria (CindU) is a condition characterized by the appearance of recurrent wheals, angioedema, or both as a response to specific and reproducible triggers. Objective We sought to systematically assess evidence on the efficacy and safety of treatment options for CindU. Results were used to inform the 2017 update of "The EAACI/GA 2 LEN/EDF/WAO guideline for the definition, classification, diagnosis and management of urticaria." Methods Randomized controlled trials and controlled intervention studies were searched systematically in various databases. Included studies were evaluated with the Cochrane Risk of Bias tool. Where possible, results from single studies were meta-analyzed, applying the Mantel-Haenszel approach by using a random-effects model (Der Simonian–Laird). Results We identified 30 studies that included patients with cold urticaria, symptomatic dermographism, delayed-pressure urticaria, or cholinergic urticaria. No studies on other forms of CindU were eligible. Risk of bias was often rated as unclear or high. Overall, second-generation antihistamines were more effective than placebo, and available data indicate that updosing might be effective. Omalizumab proved effective in patients with symptomatic dermographism, who did not respond to antihistamines. Detailed results are given for each type of CindU. Conclusions The available evidence is limited by small samples, heterogeneous efficacy outcomes, and poor reporting quality in many of the included studies. The findings are congruent with the suggested stepwise approach to treating CindUs. However, the data do not allow for drawing specific conclusions for specific subtypes of CindU.