Linalool - a significant contact sensitizer after air exposure

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)

Contact allergy trends in Sweden - a retrospective comparison of patch test data from 1992, 2000, and 2009

Background. Contact allergy prevalence rates change over time as a result of variations in allergen exposure. Data from patch test clinics are often used as markers for allergy trends. Objectives. The aim of the present retrospective study was to describe trends in rates of sensitization to allergens in the Swedish baseline series. Patients/materials/methods. Prevalence rates are described by comparing consecutive patch test data from 1992, 2000 and 2009 in Swedish patch test clinics. In total, 3680 patients were included in 1992, 3825 in 2000, and 3112 in 2009. Results. Among test substances with a sensitization rate above 2% in 2009, significant decreases were noted for nickel sulfate, cobalt chloride, colophonium, and methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI), and a significant increase for p-phenylenediamine, as compared with 1992. Potassium dichromate reactions had increased among younger women, whereas reactions to nickel and cobalt had decreased in this group. Sensitization to chromium, cobalt and fragrance mix I had decreased among older men, and sensitization to nickel had decreased among younger men. Conclusions. It is probable that these changes in 1992-2009 reflect both changes in regulations for nickel, lower levels of chromium in cement and of MCI/MI in cosmetics, and increasing use of hair dyes

Patch Testing with a Textile Dye Mix in Two Concentrations : A Multicentre Study by the Swedish Contact Dermatitis Research Group

Disperse dyes, which are used for colouring synthetic textile fibres, are well-known contact sensitisers. To investigate the outcome of patch-testing with a textile dye mix (TDM) at 7 dermatology clinics in Sweden, a TDM tested at 2 concentrations was included into the baseline series during one year. The mix consisted of Disperse (D) Blue 35, D Yellow 3, D Orange 1 and 3, D Red 1 and 17, all 1.0%, and D Blue 106 and D Blue 124, each 0.3% in the mix 6.6% and 1.0% each in the mix 8.0%. In 2,122 tested patients, contact allergy to the TDM at the concentration 8.0% was found in 2.8% and to the TDM at 6.6% in 2.5% of the patients. The contact allergy to the TDM could explain or contribute to the dermatitis in about 35% of the patients. Conclusion: contact allergy to the TDM is common and inclusion into the Swedish baseline series should be considered

Patch Testing with a Textile Dye Mix in Two Concentrations : A Multicentre Study by the Swedish Contact Dermatitis Research Group

Disperse dyes, which are used for colouring synthetic textile fibres, are well-known contact sensitisers. To investigate the outcome of patch-testing with a textile dye mix (TDM) at 7 dermatology clinics in Sweden, a TDM tested at 2 concentrations was included into the baseline series during one year. The mix consisted of Disperse (D) Blue 35, D Yellow 3, D Orange 1 and 3, D Red 1 and 17, all 1.0%, and D Blue 106 and D Blue 124, each 0.3% in the mix 6.6% and 1.0% each in the mix 8.0%. In 2,122 tested patients, contact allergy to the TDM at the concentration 8.0% was found in 2.8% and to the TDM at 6.6% in 2.5% of the patients. The contact allergy to the TDM could explain or contribute to the dermatitis in about 35% of the patients. Conclusion: contact allergy to the TDM is common and inclusion into the Swedish baseline series should be considered

Patch testing with formaldehyde 2.0% in parallel with 1.0% by the Swedish Contact Dermatitis Research Group

In a multicentre study consecutively patch-tested dermatitis patients were tested simultaneously with 1.0% and 2.0% (w/v) formaldehyde in aqua applied with a micropipette (15 µl) to the filter paper disc in Finn Chambers (0.30 mg/cm2 and 0.60 mg/cm2, respectively). A total of 2,122 dermatitis patients were patch-tested. In all, 77 (3.6%) patients reacted positively to formaldehyde; 37 reacted only to 2.0%, 35 reacted to both concentrations and 5 patients reacted only to 1.0%. Significantly more patients were thus diagnosed with contact allergy to formaldehyde with 2.0% compared to 1.0% (p < 0.001) without causing more irritant reactions. The detected number of isolated allergic reactions to the 2 formaldehyde-releasers in the Swedish baseline series and not to formaldehyde itself raises the question whether quaternium-15 1.0% and diazolidinyl urea 2.0% should be present in the Swedish baseline series

Suitable test concentration of cobalt and concomitant reactivity to nickel and chromium. A multicentre study from the Swedish Contact Dermatitis Research Group

Background: In Sweden, cobalt chloride 0.5% has been included in the baseline series since the mid-1980s. A recent study from Stockholm showed that cobalt chloride 1% petrolatum (pet.) was more suitable than 0.5%. Cobalt chloride at 1.0% has been patch tested for decades in many European countries and around the world. Objectives: To study the suitability of patch testing to cobalt 1.0% vs 0.5% and to analyze the co-occurrence of allergy to cobalt, chromium, and nickel. Results: Contact allergy to cobalt was shown in 90 patients (6.6%). Eighty (5.9%) patients tested positive to cobalt 1.0%. Thirty-seven of the 90 patients (41.1%) with cobalt allergy were missed by cobalt 0.5% and 10 (0.7%) were missed by cobalt 1.0% (P <.001). No case of patch test sensitization was reported. Allergy to chromium was seen in 2.6% and allergy to nickel in 13.3%. Solitary allergy to cobalt without nickel allergy was shown in 61.1% of cobalt-positive individuals. Female patients had larger proportions of positive reactions to cobalt (P =.036) and nickel (P <.001) than males. Conclusion: The results speak in favor of replacing cobalt chloride 0.5% with cobalt chloride 1.0% pet. in the Swedish baseline series, which will be done 2021

Multicentre patch testing with compositae mix by the Swedish contact dermatitis research group

Sesquiterpene lactone mix detects contact allergy to these compounds present in the plant family Asteraceae. This marker is present in many baseline series. An additional marker is Compositae mix, which is not present in many baseline series. To investigate whether this allergen should be inserted into the Swedish baseline series, sex dermatology centres representing the Swedish Contact Dermatitis Research Group included Compositae mix into their baseline series for 1.5 years. Of 2818 patients tested, 31 (1.1%) reacted to Compositae mix and 26 (0.9%) to Sesquiterpene lactone mix. Active sensitization to Compositae mix was noted in two cases. Only 0.4% of Asteraceae contact allergy cases would have been missed if Compositae mix had not been tested, a frequency too low to merit its inclusion in the baseline series. Due to obvious geographical differences in frequency in frequency of simultaneous allergic reactions to Compositae mix and Sesquiterpene lactone mix, the question as to whether specific baseline series (including Compositae mix or not as a "tail" substance) should be used in the different centres must be addressed. Another option could be to remove Sesquiterpene lactone mix from the baseline series and substitute it with Compositae mix

Patch testing with formaldehyde 2.0% in parallel with 1.0% by the Swedish Contact Dermatitis Research Group

In a multicentre study consecutively patch-tested dermatitis patients were tested simultaneously with 1.0% and 2.0% (w/v) formaldehyde in aqua applied with a micropipette (15 µl) to the filter paper disc in Finn Chambers (0.30 mg/cm2 and 0.60 mg/cm2, respectively). A total of 2,122 dermatitis patients were patch-tested. In all, 77 (3.6%) patients reacted positively to formaldehyde; 37 reacted only to 2.0%, 35 reacted to both concentrations and 5 patients reacted only to 1.0%. Significantly more patients were thus diagnosed with contact allergy to formaldehyde with 2.0% compared to 1.0% (p &lt; 0.001) without causing more irritant reactions. The detected number of isolated allergic reactions to the 2 formaldehyde-releasers in the Swedish baseline series and not to formaldehyde itself raises the question whether quaternium-15 1.0% and diazolidinyl urea 2.0% should be present in the Swedish baseline series

Not only oxidized R-(+)- but also S-(-)-limonene is a common cause of contact allergy in dermatitis patients in Europe

Limonene, one of the most often used fragrance terpenes in any kind of scented products, is prone to air-oxidation. The oxidation products formed have a considerable sensitizing potential. In previous patch test studies on consecutively tested dermatitis patients, oxidized R-limonene has been proven to be a good and frequent indicator of fragrance-related contact allergy. The current study extends these investigations to 6 European clinics of dermatology, where the oxidation mixture of both enantiomers of limonene (R and S) have been tested in 2411 dermatitis patients. Altogether, 63 out of 2411 patients tested (2.6%) reacted to 1 or both the oxidized limonene preparations. Only 2.3% reacted to the oxidized R-limonene and 2.0% to the oxidized S-limonene. In 57% of the cases, simultaneous reactions were observed to both oxidation mixtures. Concomitant reactions to the fragrance mix, colophonium, Myroxylon pereirae, and fragrance-related contact allergy were common in patients reacting to 1 or both the oxidized limonene enantiomers. Our study provides clinical evidence for the importance of oxidation products of limonene in contact allergy. It seems advisable to screen consecutive dermatitis patients with oxidized limonene 3% petrolatum, although this patch test material is not yet commercially available