| 11. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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Limonene hydroperoxide analogues differ in allergenic activity
- 2008
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 59:6, s. 344-352
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Tidskriftsartikel (refereegranskat)abstract
- Background: The fragrance terpene R-limonene is a very weak sensitizer but forms allergenic oxidation products upon contact with air. Oxidized (ox.) limonene is a frequent cause of contact allergy in clinical testing. Objectives: This study investigates the sensitizing potencies of ox. and non-ox. limonene and of structurally closely related limonene hydroperoxides. The clinical importance of the difference in sensitizing potency of two hydroperoxides in autoxidized limonene was studied. Patients/Methods: Ox. and non-ox. limonene were investigated in the murine local lymph node assay (LLNA). Limonene hydroperoxides were investigated using a modified LLNA involving non-pooled lymph nodes and statistical calculations; patch testing of patients with known contact allergy to ox. limonene was performed. Results: A marked increase in the sensitizing potency of ox. limonene compared with that of pure limonene was observed in the LLNA. One analogue, limonene-1-hydroperoxide, was a significantly more potent sensitizer than the other hydroperoxides and gave more positive test reactions in the allergic patients. Conclusions: The results support that hydroperoxides have a specific reactivity indicating that oxygen-centred radicals are important in hapten–protein complex formation of hydroperoxides. The primary oxidation products of ox. limonene, the hydroperoxides, have an important impact on the sensitizing capacity of the oxidation mixture.
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| 12. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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Limonene hydroperoxide analogues show specific patch test reactions.
- 2014
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Ingår i: Contact dermatitis. - : Wiley. - 1600-0536 .- 0105-1873. ; 70:5
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Tidskriftsartikel (refereegranskat)abstract
- The fragrance terpene R-limonene is a very weak sensitizer, but forms allergenic oxidation products upon contact with air. The primary oxidation products of oxidized limonene, the hydroperoxides, have an important impact on the sensitizing potency of the oxidation mixture. One analogue, limonene-1-hydroperoxide, was experimentally shown to be a significantly more potent sensitizer than limonene-2-hydroperoxide in the local lymph node assay with non-pooled lymph nodes.
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| 13. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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Linalool - a significant contact sensitizer after air exposure
- 2010
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 62:1, s. 32-41
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Tidskriftsartikel (refereegranskat)abstract
- Background: Linalool is a widely used fragrance terpene. Pure linalool is not allergenic or a very weak allergen, but autoxidizes on air exposure and the oxidation products can cause contact allergy. Oxidized (ox.) linalool has previously been patch tested at a concentration of 2.0% in petrolatum (pet.) in 1511 patients, and 1.3% positive patch test reactions were observed. Objective: To investigate the optimal patch test concentration for detection of contact allergy to ox. linalool. Methods: Four concentrations of ox. linalool (2.0%, 4.0%, 6.0%, 11.0% pet.) were tested in 3418 consecutive dermatitis patients. Results: Ox. linalool 2.0%, 4.0%, 6.0%, and 11.0% pet. detected positive patch test reactions in 0.83%, 3.2%, 5.3%, and 7.2% of the tested patients, respectively. The doubtful reactions increased with rising concentrations but relatively less, giving 5.1%, 6.4%, and 7.3% doubtful reactions, respectively, for ox. linalool 4.0%, 6.0%, and 11.0% pet. Few irritative reactions were seen. Conclusions: Raising the patch test concentration for ox. linalool gave a better detection of contact allergy, as many as 5-7% positive patch test reactions were detected. We suggest a patch test concentration of ox. linalool 6.0% pet. for future patch testing, giving a dose per unit area of 2.4 mg/cm(2) when 20 mg test substance is tested in small Finn Chambers (R).
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| 14. |
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| 15. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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Positive patch test reactions to oxidized limonene: exposure and relevance
- 2014
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 71:5, s. 264-272
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Tidskriftsartikel (refereegranskat)abstract
- Background. R-Limonene is a common fragrance terpene found in domestic and industrial products. R-Limonene autoxidizes on air exposure, and the oxidation products can cause contact allergy. In a recent multicentre study, 5.2% (range 2.3-12.1%) of 2900 patients showed a positive patch test reaction to oxidized R-limonene. Objective. To study the exposure to limonene among consecutive dermatitis patients reacting to oxidized R-limonene in an international setting, and to assess the relevance of the exposure for the patients' dermatitis. Methods. Oxidized R-limonene 3.0% (containing limonene hydroperoxides at 0.33%) in petrolatum was tested in 2900 consecutive dermatitis patients in Australia, Denmark, the United Kingdom, Singapore, Spain, and Sweden. A questionnaire assessing exposure to limonene-containing products was completed. Results. Overall, exposure to products containing limonene was found and assessed as being probably relevant for the patients' dermatitis in 36% of the limonene-allergic patients. In Barcelona and Copenhagen, >70% of the patients were judged to have had an exposure to limonene assessed as relevant. Conclusions. Oxidized R-limonene is a common fragrance allergen, and limonene was frequently found in the labelling on the patients' products, and assessed as relevant for the patients' dermatitis. A large number of domestic and occupational sources for contact with R-limonene were identified.
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| 16. |
- Engfeldt, Malin, et al.
(författare)
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Can patch testing with methylchloroisothiazolinone/methylisothiazolinone be optimized using a new diagnostic mix? - A multicenter study from the Swedish Contact Dermatitis Research Group
- 2020
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 82:5, s. 283-289
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Tidskriftsartikel (refereegranskat)abstract
- Background Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and methylisothiazolinone (MI) are tested to detect contact allergy to these isothiazolinones. Objectives To study if an aqueous patch test preparation with MCI and MI in a mix of 0.015% and 0.2%, respectively, detects more contact allergies than the commonly used preparations of MCI/MI in 0.02% aq. and MI in 0.2% aq. Methods A total of 1555 patients with dermatitis in five Swedish dermatology departments were tested consecutively with MCI/MI 0.215% aq., MCI/MI 0.02% aq., and MI 0.2% aq. Results The share of contact allergy to MCI/MI 0.215% aq., MCI/MI 0.02% aq., and MI 0.2% aq. varied in the test centers between 7.9% and 25.9%, 3.2% and 10.3%, and 5.8% and 12.3%, respectively. MCI/MI 0.215% aq. detected significantly more patch-test positive individuals than both MCI/MI 0.02% aq. (P < .001) and MI 0.2% aq. (P < .001), as well as either one of MCI/MI and MI (P < .001). In the patients only reacting to MCI/MI 0.215% aq., 57.7% were recorded as having a dermatitis that was explained or aggravated by exposure to either MCI/MI or MI. Conclusion The results speak in favor of replacing the preparations MCI/MI 0.02% aq. and MI 0.2% aq. with MCI/MI 0.215% aq. as the screening substance in the Swedish baseline series, which has been implemented in 2020.
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| 17. |
- Engfeldt, Malin, et al.
(författare)
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Swedish Experiences From Patch-testing Methylisothiazolinone Separately
- 2015
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 95:6, s. 717-719
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Tidskriftsartikel (refereegranskat)abstract
- The preservative methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) is a well-known sensitiser and present in the Swedish baseline series since the 1980s. The proportions of MCI/MI are 3:1. MI alone has been used as a preservative since less than 10 years. This study was conducted on behalf of the Swedish Contact Dermatitis Research Group to evaluate inclusion of MI in the Swedish baseline series since the preparation of MCI/MI might fail to detect contact-allergic reactions to MI alone. Patients with suspected allergic contact dermatitis at 5 Swedish dermatology departments were consecutively patch-tested with MI 2,000 ppm aq and MCI/MI 200 ppm aq. The number of cases with exclusive contact allergy to MI varied between 0.8-4.2%. In total, 1.9% reacted exclusively to MI and not to MCI/MI. Due to the considerable frequency of contact allergy to MI not traced by MCI/MI, MI 2,000 ppm aq is included in the Swedish baseline series from January 2014. This corresponds to a dose of 60 mu g/cm(2).
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| 18. |
- Hagvall, Lina, 1978, et al.
(författare)
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Air-oxidized linalyl acetate - an emerging fragrance allergen?
- 2015
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Ingår i: Contact dermatitis. - : Wiley. - 1600-0536 .- 0105-1873. ; 72:4, s. 216-23
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 19. |
- Hagvall, Lina, 1978, et al.
(författare)
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Concomitant reactions to geraniol and citral – due to cross reactivity?
- 2012
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Ingår i: Contact Dermatitis. - 1600-0536. ; 66:s2, s. 66-87
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Konferensbidrag (refereegranskat)abstract
- Background: Fragrance allergy is estimated as the second most common contact allergy in the western world, based on test results using the fragrance markers in the baseline series. One of these markers, fragrance mix (FM), contains geraniol at a concentration of 1%. Although about 10% of tested consecutive dermatitis patients react to FM, geraniol is responsible for only 5% of positive patch test reactions to the individual components of FM. However, we have shown that geraniol forms sensitizing compounds via autoxidation and skin metabolism. Geranial and neral, the two isomers in citral, are the major haptens formed in both of these activation pathways. Objectives: To investigate whether testing with oxidized (ox) geraniol detects more cases of contact allergy than testing with pure geraniol. The pattern of reactions to pure and ox geraniol, and the metabolites/autoxidation products geranial and neral was studied to investigate the importance of autoxidation or cutaneous metabolism in contact allergy to geraniol. Patients and methods: Pure and ox geraniol were tested at 2.0% pet in 2227 and 2179 consecutive patients, respectively. In parallel, geranial, neral and citral were tested in 2152, 1626, and 1055 consecutive patients, respectively. Results: Pure and ox geraniol detected positive patch test reactions in 0.13% and 0.55% of the patients, respectively. Eight of 11 patients with positive patch test reactions to ox geraniol also reacted to citral or its components. Relevance for the positive patch test reactions in relation to the patients´ dermatitis was found in 11 of 14 cases. Conclusions: Testing with ox geraniol could detect more cases of contact allergy to geraniol. The reaction pattern of the 14 cases presented indicates that both autoxidation and metabolism could be important in sensitization to geraniol. Concomitant reactions for geraniol and citral could be due to cross reactivity.
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| 20. |
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