CLINICAL USES OF 2,3-DIMERCAPTOPROPANOL (BAL). V. SKIN SENSITIZATION TO BAL 1

Abstract

When applied to normal undamaged skin, 5% BAL in grease ointment, 5% BAL in carbowax ointment, and 5% BAL in ethylene glycol all produced definite sensitization and sensitization dermatitis in 19% of the 88 human subjects exposed. The 3 vehicles caused no significant difference in the sensitizing capacity of BAL. When applied to damaged (chemically burned) skin, 5% and 10% BAL ointments and/-or undiluted BAL produced definite sensitization and sensitization dermatitis in 35 of 53 human subjects. Although the series is too small to permit definite conclusions, the results suggest that there may be a significant difference in incidence of sensitization between those subjects who received BAL applications to the damaged (burned) site on only one arm (36% of 14 subjects) and those who received BAL applications to burned sites on both arms (77% of 39 subjects). The above results may be explained by the fact that the presence of devitalized tissue at the site of application in burned areas permits the ready combination of BAL with pro-teins, or other larger molecules, and the formation of complexes with a high capacity to sensitize. The sensitivity produced by BAL was neither the classic eczematous contact-type nor the classic urticarial type of skin sensitivity. It differed somewhat from both of these common types and consisted of erythema, edema and papules upon external exposure of the skin to the allergen. While the sensitivity to BAL did not remain strictly confined to the areas of exposure, in the majority of individuals the exposed area was more sensitive than other parts. There was evidence that in exceptional cases the sensitivity may remain practically restricted to the previously exposed parts. The sensitivity produced by BAL was not confined strictly to BAL, for the majority of sensitized individuals reacted also to patch tests with at least 2 chemically related compds. The repeated intramusc. injn. of BAL produced skin sensitization as demonstrated by positive patch tests in 5 of 18 subjects. When a large dose of BAL was again injected intramusc, in 4 of these subjects whose skin had become hypersensitive to BAL, no cutaneous reactions were produced.