`© 2011 Informa Healthcare USA, Inc.
`ISSN 1556-9527 print/ISSN 1556-9535 online
`DOI: 10.3109/15569527.2011.554484
`
`CASE REPORT
`
`Hydroxyisohexyl 3-cyclohexene carboxaldehyde (Lyral®) as
`allergen: experience from a Contact Dermatitis Unit
`
`Rodrigo Carvalho, Paula Maio, Cristina Amaro, Raquel Santos, and Jorge Cardoso
`
`Curry Cabral Hospital, Dermatology and Venereology Department, Lisbon, Portugal
`
`Abstract
`Introduction: Hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC)—Lyral® is a widely used synthetic fragrance
`found in personal care and household products. It is an aldehyde, lipophilic enough to penetrate the skin and is a
`frequent cause of contact sensitization.
`Objective: Describe the frequency of contact allergy to HICC in a Contact Dermatitis Unit, after its inclusion in baseline
`patch test series.
`Methods: A retrospective study including all patients submitted to patch test, from January 2007 to December 2009.
`Results: Over a 3-year period, 629 consecutive patients were patch tested. The frequency of positive reactions to
`HICC was 2.7% (17/629). Of the positive patients, 35% (6/17) gave a history of atopy, 58.8% (10/17) had eczema on
`the face and neck, 23.5% (4/17) on the hands, 23.5% (4/17) in the axillae, 17.6% (3/17) on the trunk and 6% (3/17)
`had generalized eczema. All patients were patch positive for more than one allergen: all (17/17) positive to fragrance
`Mix 2 (FM2); 47% of the patients (8/17) positive to fragrance Mix 1 (FM1); and 23.5% of the patients (4/17) positive to
`Balsam of Peru. In 94% (16/17) of cases, the reaction was judged to be of current relevance.
`Discussion: The frequency of positive reactions to HICC of 2.7% found in our population is according to what is
`described in several European reports, where HICC is still widely used as a fragrance ingredient. In contrast, in North
`America, the prevalence is lower. All the patients were positive also to FM2. The association found between reactions
`to FM1 and HICC is also commonly reported and could represent a concomitant sensitization following increased
`exposure to fragrance allergens. These data confirm the importance of HICC introduction in the baseline patch test
`series.
`Keywords: Contact dermatitis, hydroxyisohexyl 3-cyclohexene carboxaldehyde, patch test
`
`Introduction
`carboxaldehyde
`3-cyclohexene
`Hydroxyisohexyl
`(HICC), also known as Lyral®, is one of the fragrances
`published in the Fenn Study in 1989 (1). Since then, it
`is a widely used synthetic fragrance found in personal
`care and household products. The frequency of HICC
`as an ingredient in these products is quoted as being
`between 33% and 46% in European countries. It is an
`aldehyde, lipophilic enough to penetrate the skin and
`is a frequent cause of contact sensitization (2). Over
`the past decade, routine patch testing has shown that
`1.5–3% of eczema patients have positive patch tests to
`
`HICC, making it a common contact allergen through-
`out Europe (3–5). Therefore, it has been included in the
`European baseline patch test series (6). Also, the use of
`HICC in cosmetic products was unrestricted until 24
`April 2003. At that time, a limit of 1.5% in both leave-on
`and rinse-off products were set by the International
`Fragrance Association (7). The rationale behind this
`limit is unknown, but some reports suggest that this
`intervention has not had any effect (8). In this study,
`the authors describe the frequency of contact allergy to
`HICC in a Contact Dermatitis Unit, after its inclusion in
`baseline patch test series.
`
`Address for Correspondence: Rodrigo Carvalho, Curry Cabral Hospital, Dermatology and Venereology Department, Lisbon, Portugal. E-mail:
`rodrigoaraujocarvalho@gmail.com
`
`(Received 19 December 2010; revised 05 January 2011; accepted 07 January 2011)
`
`249
`
`Petitioner Dr. Squatch
` Ex. 1030
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`250 R. Carvalho et al.
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`Methods
`A retrospective study including all patients submitted
`to patch test, from January 2007 to December 2009.
`Epicutaneous tests were applied on the upper back
` during 2 days using Finn Chambers®, and a positive patch
`test reaction was defined according to International
`Contact Dermatitis Research Group (ICDRG) guide-
`lines (9). Readings were performed at 48 and 96 h. All
`patients were tested with the European baseline series
`(with additions from the Portuguese Contact Dermatitis
`Study Group).
`
`Results
`Over a 3-year period, 629 consecutive patients were
`patch tested. The frequency of positive reactions to HICC
`was 2.7% (17/629). All reactions were (+) or (++). Of the
`17 patients with a positive reaction, 59% (10/17) were
`female and 41% (7/17) were male. The average age of all
`HICC positive reaction patients was 45 years old (mean
`44.64; SD 14.90). Of the patients with a positive reaction,
`35% (6/17) gave a history of atopy. The clinical diagnosis
`of eczema was made for all patients with positive reac-
`tion to HICC, localized in the face and neck in 58.8%
`(10/17), hands in 23.5% (4/17), axillae in 23.5% (4/17),
`trunk in 17.6% (3/17) and generalized in 6% (3/17). All
`patients were patch positive for more than one allergen:
`all (17/17) positive to fragrance Mix 2 (FM2); 47% of the
`patients (8/17) positive to fragrance Mix 1 (FM1); and
`23.5% of the patients (4/17) positive to Balsam of Peru.
`In 94% (16/17) of cases, the reaction was judged to be of
`current relevance for products used in personal hygiene
`like perfumes, deodorants and hair conditioners.
`
`Discussion
`The frequency of positive reactions to HICC of 2.7%
`found in our population is according to what is described
`in several European reports (1.5–3%) (2–4), where HICC
`is still widely used as a fragrance ingredient. In con-
`trast, in North America, the prevalence was found to be
`only 0.4%, which was considered to be mainly because
`of the presence of the ingredient in higher concentra-
`tions in deodorants in the EU compared with the USA
`(10,11).
`All the patients from our study that were positive to
`HICC were positive to FM2, what is expected since HICC
`
`belongs to the mix present in FM2. Also, from the HICC
`positive patients, 47% were positive to FM1. This asso-
`ciation found between reactions to FM1 and HICC in our
`series is also commonly reported in several reports and
`could represent a concomitant sensitization following
`increased exposure to fragrance allergens (5).
`These data support current reports that HICC is a
`common allergen and confirm the importance of HICC
`introduction in the baseline patch test series.
`
`Declaration of interest
`The authors report no declarations of interest.
`
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