Patch Test Reactions to Merthiolate in Healthy Young Subjects

A high incidence of positive patch tests to merthiolate (thimerosal) has been observed in young adult males without previous or present skin disease. In battery‐tested clinical material several positive merthiolate tests occurred, mainly in the younger age groups, while a high‐age group did not react even to a strong merthiolate patch test. Although the clinical and histological features of the reaction are mainly of an allergic type, evidence is presented that the merthiolate reaction should be considered a false positive test, peculiar to that substance and to young skin.