Lack of cross-reaction between DNCB and chloramphenicol.

Although one study has reported a cross-reactivity between DNCB and chloramphenicol in 40% of patients, other investigators have been unable to confirm the existence of any cross reaction. The purpose of this study is to determine whether sensitization of patients to DNCB poses a risk of cross reaction to chloramphenicol. In the present study, 100 consecutive patients who were sensitized to DNCB failed to show a single reaction to patch testing with chloramphenicol in a 1% ointment. The discrepancy between these results may be explained by a possible misinterpretation of a primary irritant reaction as an allergic contact reaction in the original report.