Association between allergic conjunctivitis and provisional tic disorder in children

Background Allergic diseases are associated with a higher risk of Tourette's syndrome (TS). Provisional tic disorder (PTD) and eye blinking are often reported as the initial symptoms both in TS and in allergic conjunctivitis (AC). Objective To investigate the association between AC and PTD in children of 4-10 years of age in southwest China. Methods This case-control study was carried out at the Children's Hospital of Chongqing Medical University between January 2016 and June 2017. Age- and gender-matched children without PTD were included as the control group. Intraocular pressure was measured by non-contact tonometry, tear film break-up time by slit-lamp examination, and allergens by skin prick test (SPT). Multivariable logistic regression analysis was applied to adjust for the simultaneous effects of AC, dry eye, and allergic history in children with PTD. Results The frequency of AC was higher in the PTD group (74.3%, 52/70) than in the control group (17.1%, 12/70) (P < 0.001). The frequencies of positive SPT were found to be higher in the PTD group (80.0%, 56/70) than in the control group (20.0%, 14/70). AC, dry eye, and history of allergic rhinitis were significantly associated with PTD. Conclusion The frequencies of AC are high in children with PTD. AC and dry eye may be both associated with PTD in children.