Methods: This single-centre retrospective study identified 96 patients with CSU below 18 years of age who were followed in our allergy clinic for 6 months. Disease-related factors such as occurrence of urticaria, angioedema and anaphylaxis as well as familial history, environmental exposures, co-morbid allergies, immunological investigations and drug treatments were retrieved from medical records. Patients were considered to be in remission when they were symptom-free for 3 months. Natural history of CU was delineated by Kaplan-Meier analysis, and factors associated with disease remission were analysed by log-rank statistics.
Results: The mean (SD) age of patients at baseline was 9.0 (5.2) years, and 53 (55%) of them were male. They were followed for a median of 4.0 years. Coexisting asthma, rhinitis and eczema affected 47%, 51% and 24% of these patients. Sixty-seven percent (53/79) of patients were atopic. Forty-seven (49%) patients had urticarial episodes at least once weekly, and 33 patients had both urticaria and angioedema. Both patients who developed anaphylaxis (one respiratory and one cardiorespiratory) had persistent disease. Seventy-nine patients had concomitant inducible urticaria. Laboratory investigations revealed positive anti-nuclear antibody in 26% (12/47; none with anti-thyroid antibodies), circulating eosinophilia in 24% (14/59), increased serum total IgE in 68% (40/59) and low plasma C3 and/or C4 levels in 30% (16/53). Fifty-six patients were treated with non-sedating antihistamines alone and 15 had combined non-sedating antihistamines and H2 antagonists. Sixty (63%) patients were in remission at a median of 2.4 years from disease onset. None of the clinical and laboratory parameters was associated with disease remission.
Conclusions: Childhood CU has in general favourable prognosis, and two-thirds of them achieve disease remission. This study cannot identify any clinical or laboratory factor for the resolution of CU.
Funding: Direct Grant for Research (2013.2.033), CUHK