Sensitization to thimerosal in atopic children

Thimerosal is an organic mercurial compound widely used as a preservative i n vaccines, eyedrops, and contact lens cleaning and storage solutions. 5 in fants, 2 female and 3 male, ranging in age from 7 to 28 months and affected by atopic dermatitis (AD) diagnosed according to the Hanifin and Rajka cri teria, experienced an exacerbation of their clinical condition 2-10 days af ter mandatory vaccinations with vaccines containing thimerosal. Cutaneous l esions of nummular eczema appeared on the trunk, limbs and face. All patien ts were patch tested with serial dilutions of thimerosal in petrolatum. A p ositive patch test reaction to thimerosal 0.1% pet. was observed in all 5 c hildren. 3 of them also showed a positive reaction at 0.01% and 0.05% pet. Despite their thimerosal-hypersensitivity, all children completed the entir e series of mandatory vaccinations, care being taken to use different needl es for injection and aspiration of the vaccine. The 2-year followup did not reveal other episodes of exacerbation of the AD after vaccination. The pre sent study confirms the high frequency of sensitization to thimerosal in at opic children and suggests that vaccination can cause clinical symptoms in sensitized children. Nevertheless, sensitization to thimerosal does not pre vent children from continuing with mandatory vaccinations.