Hydroxyisohexyl 3-cyclohexene carboxaldehyde- known as Lyral: quantitative aspects and risk assessment of an important fragrance allergen.

Hydroxyisohexyl 3-cyclohexene carboxaldehyde, also known as Lyral, is a fragrance ingredient identified as the cause of contact allergic reactions in 2-3% of eczema patients undergoing patch testing. Lyral has been included in the standard patch test series in many clinics due to its importance as an allergen. It has been used without restrictions in cosmetic products, until now. In the present study, the dose-response relationship of Lyral contact allergy was studied with doses relevant for normal exposure in cosmetic products. 18 eczema patients, who previously had given a positive patch test to Lyral 5% petrolatum, were included along with 7 control subjects. All cases were tested with a serial dilution of Lyral in ethanol 6% to 6 p.p.m and subjected to a 2-week, repeated open application test with a low dose of Lyral in ethanol. In the case of no reaction, this was followed by another 2 weeks of testing with a higher dose. The test was performed at the volar aspect of the forearm. In 16 of 18 cases (89%), a positive use test developed, 11 reacting to the low and 5 to the high concentration. None reacted to the vehicle control of ethanol applied to the contralateral arm. All controls were negative to both the test solutions of Lyral and the ethanol control. The difference between the test and the control group was statistically significant (Fisher's test, P < 0.001). It is concluded that Lyral at the current usage levels is inducing sensitization in the community. The same levels were shown to elicit allergic contact dermatitis in almost all sensitized individuals. A significant reduction in usage concentrations is recommended to prevent contact allergic reactions.

An update of the risk assessment for methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) with focus on rinse-off products.

Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) has been widely used during the last 20 years for the preservation of aqueous systems in cosmetics, toiletries and in various industrial applications. MCI/MI has a broad spectrum of activity against fungi and bacteria at very low concentrations. The allergic contact potential of MCI/MI has been known for many years. This paper provides a review of pre-clinical and clinical experimental studies as well as experience from dermatology clinics worldwide. This forms the basis for an update of the risk assessment for the use of MCI/MI in rinse-off products. The scientific data indicate that the actual sensitization rate observed with a contact allergen is extremely dependent on dose and type of exposure. This review of the data leads to the conclusion that, under normal use conditions, within the current permitted/ recommended use concentrations for MCI/MI of up to 15ppm, the risk of primary sensitization from the use of rinse-off products is negligible, and elicitation of allergic contact dermatitis in MCI/MI-sensitized individuals rare, after exposure to MCI/MI-preserved rinse-off products.

Prevention of nickel allergy by regulation of specific exposures.

Nickel allergy is a cell-mediated immune response. Most cases of nickel allergy can be related to skin contact with nickel containing metallic items as buttons, suspenders, ear-ornaments etc. Epidemiological studies have shown a sensitization frequency of 20 percent in young females and 10 percent in the elderly. Two to four percent of males are sensitized. The biological significant parameter is not the nickel concentration in the alloy or coating but the amount released to the skin during exposure to human sweat. A threshold of 0.5 microgram/cm2/week has been established, where only a minor part of the nickel sensitive will react. A legislation limiting nickel exposure from specific consumer items is in force in Denmark. An expanded exposure regulation was adopted, but not yet implemented, by the EU-countries in 1994.

Comparison of 2 tests for clinical assessment of formaldehyde exposure.

The objective of the study was to obtain further experience on the applicability of 2 tests for clinical assessment of formaldehyde exposure. About 1300 products brought in by consecutive formaldehyde-sensitive eczema patients during a 2-year period were tested with both the chromotropic acid test and the acetylacetone test. The chromotropic acid test was modified by including a 2nd reading after 2 days. The outcome was identical for about 90% of the products, and 74% of the products that were positive on day 2 were also positive on day 1. More than 1/2 of the tests that scored as traces or caused problems on day 1 became positive on day 2. For products analyzed with both the chromotropic acid test (day 2 readings) and the acetylacetone test, about 80% gave identical results. Positive reactions were frequently found for hair shampoo, creams and lotions, soap and skin cleansers, make-up and dishwashing liquids. The samples causing discolouration or problems in the tests were mostly concentrated in specific product categories. Very few products caused problems in both test methods. Thus, the most convenient test can be used as the 1st choice and, for product categories causing discolouration or problems with a specific test, the other test method can be used.

Permanent disability from skin diseases. A study of 564 patients registered over a six year period.

An analysis of causes of permanent disability indicates which diseases most frequently result in chronicity and inability to work. A nation-wide study comprising all applications for permanent disability pension due to skin diseases in the period 1970--1976 was carried out. A total of 564 persons applied. The most common diagnosis was contact dermatitis followed by psoriasis and connective-tissue diseases. Allergic contact dermatitis alone accounted for 222 cases. 70% of these were due to nickel and chromium allergy. In all the diagnostic groups there was a preponderance of women except for hyperkeratotic hand eczema and genodermatoses. The frequency of the individual disorders in the present study is discussed in relation to their prevalence and prognosis in the literature.