Retrospective study of oral lichen planus and allergy to spearmint oil.

Oral lichen planus (OLP) is a chronic inflammatory disorder with significant morbidity, associated with symptoms of pain and local discomfort. The concept of contact allergy aggravating or inducing OLP is recognised, and reported allergens include amalgam, metals used in dental restoration and flavourings. To date there has been only one case report of a contact allergy to spearmint oil in a patient with a 3-year history of OLP.