Contact allergy to oxidized linalool and oxidized limonene: Patch testing in consecutive patients with dermatitis

BACKGROUND

Contact allergy to oxidized (ox.) linalool and ox. limonene has been reported to have a high prevalence, raising the question of inclusion into the baseline series. However, several important issues should be clarified and further investigated before inclusion can be warranted.

OBJECTIVES

To report the trends of ox. terpenes allergy in patients with dermatitis, features of the patch test reactions, and clinical characteristics of the patients.

METHODS

A retrospective analysis of 5773 patients was performed. All patients were patch tested with baseline series, individual ingredients of fragrance mix I and II, ox. linalool, and ox. limonene from 2013 to 2020.

RESULTS

The prevalence rates of contact allergy to ox. linalool and ox. limonene were 7.0% and 5.1%, respectively. Significantly increasing trends of contact allergy were observed. More than 95% of contact allergy cases were identified on Day 3/4. Patients with contact allergy to ox. linalool and ox. limonene were significantly younger than those with contact allergy to other fragrances and were predominantly female. Strong reactions were associated with older age and multiple fragrance allergies.

CONCLUSIONS

Contact allergy to ox. linalool and ox. limonene is becoming increasingly important, and findings show intriguing features. More studies concerning the clinical relevance before recommending these substances for screening are required.

Myroxylon pereirae (balsam of Peru): Still worth testing?

Background

Because Myroxylon pereirae (MP), or balsam of Peru, is nowadays almost not used “as such,” and fragrance mix 1 (FM1) apparently is more sensitive in detecting fragrance allergy, the usefulness of testing MP in baseline series was recently questioned.

Objectives

Identification of the number of clinically relevant patch test reactions to MP not detected by FM1.

Methods

Retrospective analysis of 12 030 patients patch tested with MP and FM1 for contact dermatitis between January 2018 and December 2019 in 13 Italian dermatology clinics.

Results

Four hundred thirty‐nine patients (3.6%) had a positive patch test reaction to MP; 437 (3.6%) had a positive patch test reaction to FM1. Positive reactions to both MP and FM1 were observed in 119 subjects (1.0%), 310 (2.6%) reacted to MP only, 304 (2.5%) to FM1 only, 5 to MP and sorbitan sesquioleate (SSO), 9 to FM1 and SSO, and 5 to MP, FM1, and SSO. Single sensitizations were clinically relevant in 75.2% of cases for MP (62.9% current, 12.3% past) and 76.3% for FM1 (70.1% current, 6.2% past).

Conclusions

Based on our results, MP appears to be still worth testing along with FM1 in baseline series, because it allows detection of a remarkable number of fragrance allergies, often relevant, which would be otherwise missed.

A negative breakdown test in a fragrance mix I-positive patient does not rule out contact allergy to its fragrance constituents

BACKGROUND

In about half of the patients reacting positive to fragrance mix I (FM I), breakdown testing remains negative. This raises the question of whether the reaction to FM I is false-positive, or the breakdown test is false-negative.

OBJECTIVES

To identify characteristics and sensitization patterns of patients positive to FM I, but not to its fragrance constituents.

PATIENTS AND METHODS

Retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK) between 2005 and 2019. Three patient groups were defined according to their reaction pattern: Group I, FM I positive and ≥1 single fragrance positive in the breakdown test (n = 1912); Group II, FM I positive and breakdown test negative (n = 1318); Group III, FM I negative (n = 19 790).

RESULTS

Regarding the pattern of concomitant reactions to other fragrances, Group II had an intermediate position between Group I and Group III. In other respects (age and sex distribution, frequency of sensitization to non-fragrance baseline series allergens), Group II rather resembled Group I.

CONCLUSIONS

Not every positive reaction to FM I in patients with negative breakdown tests is false-positive. There may be false-negative reactions to the single fragrance components when patch tested at 1% pet. Raising patch concentrations of some single fragrances is recommended.

Prevalence, concomitant reactions, and factors associated with fragrance allergy in Thailand

BACKGROUND

Fragrances are the most common cause of cosmetic contact allergy. Up-to-date information on contact allergy frequencies and relevance aids primary and secondary preventive measures.

OBJECTIVES

To determine the prevalence, associated factors, and concomitant reactions in fragrance allergy among Thais.

METHODS

This retrospective study collected data from 2012 to 2019. The patient characteristics of fragrance and nonfragrance allergy groups were compared. Concurrent positive reactions to fragrance allergens (fragrance mix [FM] I, FM II, Myroxylon pereirae resin and hydroxyisohexyl 3-cyclohexene carboxaldehyde) and other baseline-series allergens were analysed.

RESULTS

Of 1032 patients, 175 (17.0%) had fragrance allergy, with 57.7% of clinical relevance. FM I showed the highest prevalence (9.4%). The associated factors were being elderly, lesions on the extremities, metal allergy history, and long dermatitis duration. Contact allergies to epoxy resin and Compositae plants were significantly associated with fragrance allergy with an odds ratio of 5.95 (95% confidence interval [CI]: 5.21-6.80) and an odds ratio of 4.42 (95% CI: 1.58-12.36), respectively. No significant associations between colophonium (previously proposed as a fragrance marker) and fragrance allergens were found.

CONCLUSIONS

The prevalence of fragrance contact allergy remains high and should be considered in old patients presenting with long-standing eczema on the extremities. Unlike reports from other countries, varied, significant, concomitant reactions were observed.

Fragrant and sticky allergens from the pinewood: Cohabiting and coreacting

BACKGROUND

Tree moss (Pseudevernia furfuracea [L.] Zopf.), a lichen growing on conifers, is a frequent fragrance sensitizer. Previous studies have shown two subgroups of tree moss-allergic patients: a group sensitized to common allergens of tree and oak moss (Evernia prunastri), and another group sensitized to colophonium-derived allergens, which may contaminate tree moss extract.

OBJECTIVES

To report the results of including tree moss extract in the baseline series and discuss the clinical implications.

METHODS

Tree moss extract was included in the baseline series and sensitized patients were assessed for concomitant allergy to colophonium and oak moss, and the relevance of these reactions was analyzed.

RESULTS

Altogether, 22 of 632 patients (3.5%) had positive reactions to tree moss. Eight patients were sensitized to tree moss only (among fragrance allergens) and 75% had relevant reactions to colophonium. Fourteen patients were sensitized to other fragrance allergens as well and 28.5% had relevant colophonium reactions.

CONCLUSIONS

The prevalence of positive tree moss reactions is high enough to justify its inclusion in the baseline series. If tree moss is not included, patients with positive colophonium reactions should be informed of possible (false) cross-reactivity to tree moss to avoid this labeled fragrance allergen.

Contact sensitization to limonene and linalool hydroperoxides in Spain: a GEIDAC* prospective study

BACKGROUND

Limonene and linalool are common fragrance terpenes widely used in cosmetic, household and hygiene products. Their primary oxidation products formed after air exposure, the hydroperoxides, have been recognized as important contact haptens.

OBJECTIVES

To investigate the prevalence of contact allergy to hydroperoxides of limonene (Lim-OOHs) and hydroperoxides of linalool (Lin-OOHs) in Spain, and to define the optimal concentration for screening in consecutive patients.

METHODS

Three different concentrations of Lim-OOHs (0.1%, 0.2% and 0.3% pet.) and Lin-OOHs (0.25%, 0.5% and 1.0% pet.) were simultaneously tested in 3639 consecutive patients at 22 departments of dermatology in Spain.

RESULTS

Lim-OOHs at 0.1%, 0.2% and 0.3% yielded positive patch test reactions in 1.4%, 3.4% and 5.1% of the tested patients, respectively; and Lin-OOHs at 0.25%, 0.5% and 1.0% yielded positive reactions in 1.3%, 2.9% and 4.9% of the tested patients, respectively. Few irritant (1.5-1.9%) and doubtful reactions (0.4-0.5%) to both terpene hydroperoxides were registered at the highest concentrations tested.

CONCLUSIONS

Lim-OOHs and Lin-OOHs can be considered as common causes of contact allergy, and their inclusion in an extended baseline patch test series therefore seems to be appropriate. The patch test preparations of Lim-OOHs 0.3% pet. and Lin-OOHs 1.0% pet. are useful tools for screening of contact sensitization.

Oxidized limonene and oxidized linalool - concomitant contact allergy to common fragrance terpenes

BACKGROUND

Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively.

OBJECTIVE

To investigate concomitant reactions between oxidized R-limonene and oxidized linalool in consecutive dermatitis patients.

METHODS

Oxidized R-limonene 3.0% (containing limonene hydroperoxides 0.33%) and oxidized linalool 6% (linalool hydroperoxides 1%) in petrolatum were tested in 2900 consecutive dermatitis patients in Australia, Denmark, Singapore, Spain, Sweden, and the United Kingdom.

RESULTS

A total of 281 patients reacted to either oxidized R-limonene or oxidized linalool. Of these, 25% had concomitant reactions to both compounds, whereas 29% reacted only to oxidized R-limonene and 46% only to oxidized linalool. Of the 152 patients reacting to oxidized R-limonene, 46% reacted to oxidized linalool, whereas 35% of the 200 patients reacting to oxidized linalool also reacted to oxidized R-limonene.

CONCLUSIONS

The majority of the patients (75%) reacted to only one of the oxidation mixtures, thus supporting the specificity of the reactions. The concomitant reactions to the two fragrance allergens suggest multiple sensitizations, which most likely reflect the exposure to the different fragrance materials in various types of consumer products. This is in accordance with what is generally seen for patch test reactions to fragrance materials.

Air-oxidized linalyl acetate - an emerging fragrance allergen?

BACKGROUND

Linalyl acetate is a fragrance chemical that is prone to autoxidation. Exposure to linalyl acetate occurs through cosmetic products and essential oils, but is difficult to assess, as linalyl acetate is not labelled in the EU.

OBJECTIVE

To investigate the frequencies of contact allergy to oxidized linalyl acetate among dermatitis patients, and to investigate the autoxidation of linalyl acetate in terms of hydroperoxide formation and sensitization potency.

PATIENTS AND METHODS

Hydroperoxide formation in air-exposed linalyl acetate was determined with high-performance liquid chromatography. The sensitization potencies of hydroperoxides were determined with the local lymph node assay. One thousand seven hundred and seventeen patients were patch tested with oxidized linalyl acetate at 6.0% in petrolatum.

RESULTS

Of the patients, 2.2% showed positive reactions to oxidized linalyl acetate. Forty-three per cent of the positive patients also had positive patch test reactions to other fragrance markers. Linalyl acetate hydroperoxides were detected early in the autoxidation process, and accumulated to a concentration of 37% after 42 weeks of air exposure. The linalyl acetate hydroperoxides were classified as moderate sensitizers.

CONCLUSIONS

The frequency of positive reactions to oxidized linalyl acetate is comparable to that of previously studied oxidized fragrance terpenes. Oxidized linalyl acetate could thus be a common fragrance contact allergen.

Dermatotoxicologic clinical solutions: clinical management of fragrance mix #1 #2 patients?

Today's fragrances are present in more than just perfumes, having become ubiquitous in skin care products such as creams, shampoos, sun tan lotion and deodorants. While aromatics can arouse the senses, aromatic compounds applied to skin can also cause allergic contact dermatitis. This article describes diagnosis, limitations of patch testing for fragrance mix 1 and fragrance mix 2, the relevance of fragrance concentration in products, use testing of common consumer products and our current recommendations in regards to the management of fragrance contact allergy.