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Sensitization to thimerosal in atopic children
A Patrizi1, L Rizzoli, C Vincenzi
1Department of Clinical and Experimental Medicine, University of Bologna, Italy.
Insights
Thimerosal in vaccines can trigger eczema flare-ups in sensitized infants with atopic dermatitis (AD). However, these children can safely complete their vaccination schedules with precautions.
Area of Science:
- Pediatrics
- Immunology
- Dermatology
Background:
- Thimerosal, an organic mercurial compound, is a common preservative in vaccines and other medical solutions.
- Atopic dermatitis (AD) is a chronic inflammatory skin condition often associated with hypersensitivity.
- Vaccine preservatives like thimerosal have been investigated for potential roles in immune-related conditions.
Purpose of the Study:
- To investigate the clinical effects of thimerosal in infants with atopic dermatitis (AD).
- To assess the frequency of thimerosal sensitization in children with AD.
- To determine the safety of completing mandatory vaccinations in thimerosal-sensitized children.
Main Methods:
- Case study of 5 infants (7-28 months) with diagnosed AD experiencing post-vaccination exacerbations.
- Clinical observation of cutaneous lesions (nummular eczema).
- Patch testing with serial dilutions of thimerosal in petrolatum.
Main Results:
- All 5 infants showed positive patch test reactions to thimerosal, indicating sensitization.
- Three infants reacted to lower concentrations (0.01% and 0.05% pet.).
- Despite sensitization, all children completed their vaccination series without further AD exacerbations over a 2-year follow-up.
Conclusions:
- Confirms a high frequency of thimerosal sensitization in children with AD.
- Suggests that vaccination can precipitate clinical symptoms in sensitized individuals.
- Thimerosal sensitization does not preclude the completion of essential childhood vaccinations.
Abstract:
Thimerosal is an organic mercurial compound widely used as a preservative in vaccines, eyedrops, and contact lens cleaning and storage solutions. 5 infants, 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 criteria, experienced an exacerbation of their clinical condition 2-10 days after mandatory vaccinations with vaccines containing thimerosal. Cutaneous lesions of nummular eczema appeared on the trunk, limbs and face. All patients were patch tested with serial dilutions of thimerosal in petrolatum. A positive patch test reaction to thimerosal 0.1% pet. was observed in all 5 children. 3 of them also showed a positive reaction at 0.01% and 0.05% pet. Despite their thimerosal-hypersensitivity, all children completed the entire series of mandatory vaccinations, care being taken to use different needles for injection and aspiration of the vaccine. The 2-year follow-up did not reveal other episodes of exacerbation of the AD after vaccination. The present study confirms the high frequency of sensitization to thimerosal in atopic children and suggests that vaccination can cause clinical symptoms in sensitized children. Nevertheless, sensitization to thimerosal does not prevent children from continuing with mandatory vaccinations.