Contact allergy to citral and its constituents geranial and neral, coupled with reactions to the prehapten and prohapten geraniol.

Patch testing with citral, its components, or oxidized geraniol detects contact allergic reactions not detected using the baseline series. Patch testing with pure geraniol was shown to be of little value. Geranial and neral, although closely chemically related, are concluded to be separate haptens.