Incidence of allergic contact sensitization in central Chinese subjects with chronic urticaria.

BACKGROUND

Chronic urticaria (CU) can be provoked by a wide variety of causes. Some studies suggest contact sensitization may play a role in the disease.

OBJECTIVE

To investigate the incidence and distribution characteristics of allergic contact sensitization in central Chinese subjects with CU, and assess contact allergen avoidance measures in managing CU.

METHODS

Patch tests were performed, following the recommended standard procedure, with 20 selected allergens, in line with the European baseline series. All subjects with positive results were prescribed appropriate avoidance measures for the sensitizing substances, while subjects with negative results served as the control group. CU severity was assessed daily from week1 to week4 and for each subject, applying the Urticaria Activity Score.

RESULTS

42.9% (233/543) of subjects with CU showed positive reactions to one or more contact allergen(s). Potassium dichromate, benzene mix and carba mix were more common in male patients, while nickel sulfate was more frequent in females. The positive rates for different allergens varied with age and occupation. The median (interquartile range) severity scores at week 1 were 20 (14-21) and 15 (14-27) for the allergen avoidance group and control group, respectively (P>0.05); and 12 (7-15) and 14 (12-17) at week 4 (P<0.001).

CONCLUSION

The incidence of allergic contact sensitization in CU patients was high, and appropriate contact allergen avoidance measures benefitted CU management. Contact allergens may play a role in the pathogenic mechanism of CU and patch tests are an option for CU patients.