Acta Dermato-Venereologica 98-10CompleteContent | Page 8
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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.