Acta Dermato-Venereologica 98-10CompleteContent | Page 8

938 CLINICAL REPORT Carvone Contact Allergy in Southern Sweden: A 21-year Retrospective Study Liv KROONA 1 , Marléne ISAKSSON 2 , Camilla AHLGREN 3 , Jakob DAHLIN 2 , Magnus BRUZE 2 and Gunnar WARFVINGE 1 Department of Oral Pathology, Malmö University, 2 Department of Occupational and Environmental Dermatology, Lund University, Skåne University Hospital, and 3 Department of Prosthodontics, Malmö University, Malmö, Sweden 1 Carvone (l-carvone), a mint flavour in spearmint oil, is considered a mild skin sensitizer. Carvone-sensiti- zation may be linked to oral/perioral signs and oral li- chen planus, but studies are sparse. The prevalence of patch test reactions to carvone and relevant findings from the positive group were investigated. Records for patch-tested patients at the Malmö clinic, for the period 1996 to 2016, were studied. Carvone-positive and carvone-negative patients were compared regar- ding patch test data from baseline series and dental series. Dental series-tested carvone-positive patients were also compared with a matched group. A total of 147 out of 4,221 referred patients had a positive patch test to carvone. Sensitized patients had higher mean age and were primarily women; 73% had oral signs and 57% had oral lichen. Concomitant patch test reac- tions to gold, nickel and mercury were common. In the matched group-comparison carvone-positive patients had a higher frequency of oral lichen, but no difference was found in sensitization to gold and mercury. Key words: l-carvone CAS; 6485-40-1; spearmint; patch test; allergens; contact allergy; oral lichen planus; oral lichenoid le- sions. Accepted Jul 27, 2018; Epub ahead of print Aug 7, 2018 Acta Derm Venereol 2018; 98: 938–942. Corr: Liv Kroona, Oral Pathology, Malmö University, Faculty of Odonto- logy, SE-205 06 Malmö, Sweden. E-mail: [email protected] T he monoterpene carvone (l-carvone; Fig. S1a 1 ) is the chief component of spearmint oil and is widely used as a mint-flavouring agent (1). The flavour is typically found in oral healthcare products and foodstuffs, such as chewing gum and sweets. In addition to isolation from natural oils, carvone can be synthesized from d-limonene (Fig. S1b 1 ) (2) and it is also one of several oxidation products found in auto-oxidized d-limonene (3). Oral healthcare products are a major source of expo- sure, and carvone is a constituent of most toothpastes (4, 5). Carvone is considered a weak sensitizer (6) and the prevalence of contact allergy in patch-tested cohorts has been estimated to be 1.6–2.8% (7, 8). A few papers on patients’ adverse reactions to carvone or spearmint oil have reported both perioral and intraoral lesions from oral https://www.medicaljournals.se/acta/content/abstract/10.2340/00015555-3009 1 doi: 10.2340/00015555-3009 Acta Derm Venereol 2018; 98: 938–942 SIGNIFICANCE Carvone is a mint flavour found in most oral healthcare products. This study investigates the prevalence of contact allergy to carvone and describes common features of affec- ted patients. In a cohort of 4,221 tested patients 3.5% had contact allergy to carvone. These patients often had oral signs and variants of oral lichenoid lesions, which otherwise only affects a few percent of the population. These data show that soluble allergens such as flavours and fragrances can cause oral contact allergy. healthcare products, with intraoral lesions described as stomatitis or erosions associated with oral lichen planus (OLP) (9–13). Studies on patients with OLP or oral li- chenoid lesions (OLL) have shown an association with carvone or spearmint contact allergy (14–16). However, these reports have not made a clear distinction between OLP, which is considered to be an autoimmune disease, and OLL, such as contact reactions to dental materials or other lichenoid lesions not fulfilling the criteria of OLP (17, 18). The aim of this retrospective study was to estimate the prevalence of individuals with a positive patch test to carvone in Southern Sweden and to assess the characte- ristics of this group with regard to other contact allergies and clinical signs with special reference to OLP and OLL. METHODS Study population Data were obtained from a clinical database comprising all patients subjected to patch testing at the Department of Occupational and Environmental Dermatology, Skåne University Hospital in Malmö, Sweden (19). All patients patch-tested with carvone during a 21- year period between 1996 and 2016 were included in the study. Data recording Information retrieved from the database included age at time of investigation, sex, type of patch test series in which carvone was included, grading of carvone test reaction and other contact aller- gies. From patients with a positive carvone patch test, information was also collected regarding the referrer’s profession, diagnosis, clinical signs, and localization of signs related to the investigation. It was not possible to deduce from the referrals or patient records whether the patients had OLP or OLL. Therefore, all variants of lichenoid lesions will henceforth be denoted as oral lichen (OL) unless otherwise specified. This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2018 Acta Dermato-Venereologica.