Allergic load and symptom severity in children with tic disorders: a cross-sectional study

Tic disorders (TD) are associated with allergies, but the immune mechanisms and their impact on tic severity remain unclear. This study examined the immune profile in children with comorbid TD and allergic diseases (AD) to explore the graded association between allergic load index and tic severity. A total of 136 children with TD (aged 4 - 13 years) were divided into TD (n = 76) and TD + AD (n = 60) groups. Serum IgE levels were measured, tic severity was assessed by the Yale Global Tic Severity Scale (YGTSS), and a composite allergic load index was constructed. Its graded association with the YGTSS total tic score (0 - 50) was analyzed using correlation, trend, and regression methods. Compared with the TD group, the TD + AD group showed significantly greater vocal tic number, functional impairment, tIgE positivity, tIgE levels, sIgE positivity, and number of positive sIgE items (all p < 0.05). The moderate-to-severe tic group showed elevated positivity of allergic markers and more allergic diseases than the minimal/mild groups (p < 0.05). A graded association was observed, with each one‑standard‑deviation increase in the allergic load index corresponding to a 2.66‑point higher YGTSS total tic score (p < 0.001).

The allergic load index was positively associated with tic severity, showing a graded relationship. Systematic assessment of allergic status may provide clinically useful information in the evaluation of children with TD.

• Tic disorders (TD) and allergic diseases (AD) frequently co-occur in children. • Elevated IgE levels and Th2 immune bias have been observed in both conditions.

• Allergic load index, a composite measure integrating IgE levels, sIgE count, and allergic disease count, shows a graded positive association with tic severity in children with TD. • Each one‑standard‑deviation increase in the index corresponds to a 2.66‑point higher YGTSS total tic score.