Is There Evidence that Geraniol Causes Allergic Contact Dermatitis?

The fragrance material geraniol has been cited as a frequent cause of allergic contact dermatitis. A review of the literature shows that when the underlying clinical and experimental data are analyzed, a clear cause-effect relationship has infrequently or rarely been established. On the basis of the generally weak sensitizing potential of this substance coupled with its generally low exposure conditions, the prevalence of clinical cases would not be expected to be particularly high. This is not to say that geraniol is a frequent inducer of type IV allergy in members of the public. It remains to be seen, however, how often such allergy, once established, is responsible for any of the cases of allergic contact dermatitis commonly ascribed in the literature. Indeed, in some cases, patch-test conditions may not be optimal for differentiating between clinically relevant and irrelevant allergy to geraniol. Because of the numerous publications on geraniol-positive patch-test publications, a future effort to ascertain how many of these represent clinical intolerance is indicated. This will also permit determination of the NOEL (no observed effect level) in patch and use testing.