Oral contact allergy to carvone : with a focus on oral lichen

Abstract

This thesis examines carvone (l-carvone), a mint flavour, and contact allergy to carvone with a focus on oral lichen. Carvone is a constituent of spearmint oil and is used to flavour toothpaste and food. Like many flavours and fragrances, carvone may cause contact allergy, but the prevalence is low, between 1.6 and 2.8%. Affected patients often have perioral or oral signs. A couple of studies have shown that patients with oral lichen planus or oral lichenoid lesions often have contact allergy to carvone but it is not known if these lichenoid lesions are a manifestation of contact allergy or part of the auto-immune disease, oral lichen planus. In paper I, the amount of carvone was measured in 66 toothpastes and the ingredient lists were studied. Carvone was detected in all toothpastes with flavour, even fruit flavoured toothpaste, in up to 0.35%. The measured concentrations were all within the safe use level estimated to not induce contact allergy, but carvone concentrations over 0.1% are high enough to elicit a reaction in already allergic individuals. The regulation of carvone as a constituent in toothpaste was discussed. Registry data (age, sex, referring information and patch tests results) on patients with a positive patch test reaction to carvone was studied in paper II. Data was retrieved from 1996 to 2016 and was compared with other patch tested groups not allergic to carvone. A matched comparison was also made between carvone-positive and carvone-negative patients tested with the same test series. Patients with contact allergy to carvone had a high mean age and were often women. According to the referrals, they often had oral signs and

Oral lichenoid lesions in two snuff users with contact allergy to carvone

“…12 Spearmint (Mentha spicata or Mentha viridis) is a herb that belongs to the Lamiaceae family. 13 L-carvone is the main natural component of spearmint, and the content can vary according to subspecies, environmental factors, and harvest time. There are two enantiomers of carvone and limonene (Figure 2).…”

“…Up to 80% of spearmint's chemical composition is L-carvone and 10%-20% D-limonene. 13 D-limonene is chemically similar to carvone, which means that it can be transformed into carvone through a chemical process, and exposure of D-limonene to air can also lead to the formation of carvone through autooxidation. 1,3,4 The findings of simultaneous positive reactions to both carvone and oxidised limonene are thus not surprising in these patients.…”

“…There are two enantiomers of carvone and limonene (Figure 2). Up to 80% of spearmint's chemical composition is l ‐carvone and 10%–20% d ‐limonene 13 . d ‐limonene is chemically similar to carvone, which means that it can be transformed into carvone through a chemical process, and exposure of d ‐limonene to air can also lead to the formation of carvone through autooxidation 1,3,4 .…”

Dental Materials and Implants

“…Allergic individuals reacted with increased OLP/OLL and sometimes perioral eczema (Fig. 2a, b) [63].…”