Is There Evidence That Alpha-Iso-Methylionone Causes Allergic Contact Dermatitis?

Abstract

The fragrance material alpha-iso-methylionone, or ‘gamma-methylionone’, has been cited as a moderately 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 alpha-iso-methylionone is a frequent inducer of low-intensity but sub-clinical, 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 alpha-iso-methylionone. Prospective screening patch test studies combined with appropriate follow-up to ascertain clinical relevance should clarify these issues.

Identification of the causes of an allergic reaction to a fragranced consumer product

“…However, several of those may be declared on a single product and not all are associated with the same likelihood of causing or eliciting reactions in consumers. [13–22] In regions where labelling of individual fragrance ingredients is not in place, this identification may not be possible.…”

Is There Evidence that Geraniol Causes Allergic Contact Dermatitis?

“…This approach has already been used to examine four other substances that have also been cited as frequent causes of contact dermatitis: ␣ -iso-methylionone [5] , anisyl alcohol [6] , linalool [7] and amylcinnamic aldehyde [8] .…”