Aniline—A ‘Historical’ Contact Allergen? Current Data from the IVDK and Review of the Literature

Abstract

To assess whether aniline should be regarded as potential cause of contact allergy (CA). Retrospective analysis of clinical data collected in a CA surveillance network (IVDK, www.ivdk.org) between 01/1992 and 06/2004 and review of pertinent literature. In the above period, 25 of the 1119 patients patch tested with aniline had positive (allergic) reactions; in 24 of these 25 patients, CA to p-phenylenediamine, p-aminoazobenzene or (in one case) another para-amino compound was additionally diagnosed. Exposure to aniline could not be ascertained in any of the cases, based on the available data. Previous clinical results, which have been summarized and tabulated, are partly difficult to evaluate, as they may lack detail, or test concentrations are higher than those currently recommended, possibly yielding false-positive reactions. In none of the studies had previous exposures to aniline been unequivocally identified. Based on clinical data it is unlikely that aniline is an independent sensitizer of current importance. However, it may elicit allergic reactions in subjects pre-sensitized to para-substituted amino compounds. In summary, supported by recent experimental evidence employing the local lymph node assay as a validated animal test system, it appears probable that aniline is a weak allergen.