Human safety study of body lotion containing Kathon® CG

The safety of Kathon CG biocide as a preservative in leave-on body lotions was assessed by 2 double-blind studies, using similar protocols. A total of 209 healthy male and female subjects aged 18 to 65 years, 100 in California (72 test subjects, 28 controls) and 109 in Florida (88 test subjects, 21 controls) completed the studies which included pre- and post-use phase diagnostic patch testing with Kathon CG 100 ppm active ingredient, and 13 weeks daily applications of either a test lotion containing Kathon CG 15 ppm active ingredient or a control lotion without Kathon CG. No evidence of irritation or sensitization attributable to use of the biocide was found during regular dermatological examinations during the use phase. Post-use phase patch testing produced negative results in all subjects with the exception of 1 control subject in Florida who had positive readings at the 2- and 4-week post-use phase patch testing. Overall, these studies show there is minimal, if any, risk of adverse effects associated with the use of Kathon CG 15 ppm active ingredient in a leave-on application.     

Sensitization to Kathon CG in Geneva and Switzerland

Between October 1986 and June 1987 we patch tested 420 patients with Kathon CG at 100 ppm and obtained 23 positive reactions (5.5%). The other 5 Swiss university clinics joined our study between January and June 1987 and obtained sensitization rates ranging from 0.7 to 7.5%. The total mean value including Geneva was 3.6%. We did threshold patch testing in 12 patients with the following Kathon CG dilutions: 100, 50, 25, 15 and 7 ppm. We observed progressively diminishing skin reactions, especially below 25 ppm, but we still obtained slight positive reactions in 2 patients with Kathon CG at 7 ppm. Those reactions were relevant because the dermatitis disappeared when the use of Kathon-containing creams was discontinued.     

Contact allergy to methyldibromo glutaronitrile--data from a 'front line' network

The preservative methyldibromo glutaronitrile (MDBGN) has caused an epidemic of contact allergy in Europe. However, most data concerning contact allergy comes from hospital departments of dermatology. As a part of the primary health care sector, Danish dermatologists in private practice provide the front line of care for patients with skin diseases. Data from this source may therefore better reflect trends in the general population than material from hospital departments of dermatology. In this study, the frequency of MDBGN allergy and the characteristics of patients seen by dermatologists in private practice were studied. In 1 year, 2146 patients were patch tested by the participating dermatologists from 4 clinics in various parts of Denmark. 5% (110) had positive patch tests to MDBGN, with no difference between the sexes. After adjustment was made for other background variables, multivariate analysis using logistic regression showed a significant association between hand eczema and MDBGN allergy (OR 2.5, P < 0.001). In 53 cases (52.4%), the patch test reaction to MDBGN was judged to be of current relevance. Creams and lotions accounted for 31% of the identified causative products and liquid soaps for 23%. It is concluded that contact allergy to MDBGN is frequent among patients seen by dermatologists in private practice. This is consistent with results from hospital departments of dermatology in Europe and indicates a general trend and ongoing epidemic in the general population. The significant relationship between hand eczema and MDBGN allergy is of concern, and the finding that wash-off products, especially liquid soaps, play a significant role in MDBGN allergy calls for a revision of the safety assessment of MDBGN in wash-off products.     

Skin disease and contact sensitivity in house painters using water-based paints, glues and putties

A dermatologic investigation of 202 construction painters included patch testing with the TRUE Test™ standard series and ingredients of water-based paints, glues and putties (painters' series). 32 painters had current eczema and 16 had a history of previous eczema. Of these, 16 and 9, respectively, had current and previous histories of hand eczema. Irritant reactions on the hands, characterized by dry, erythematous finely fissured skin, which healed within a few days of skin rest, were found in 18 painters. 8 painters presented dry, fissured finger tips and finger sides. The total group of painters had 25 allergic reactions to the TRUE Test™ standard series and 11 to the painters' series. 11 test reactions were found to be related to present or previous hand eczema: 4 cases reacted to nickel, cobalt, colophony or N-octyl-isothiazolinone; 2 each to p-tertbutylphenol-formaldehyde resin and benzisothiazolinone (BIT); and 3 to Cl + Me-isothiazolinone, 5 painters were sensitive to BIT without clinical symptoms of skin disease. Hand eczema is no more common among construction painters who work with water-based paints, glues and putties, than in an average population. There are, however, special risks of sensitization and eczema in a construction painter's work that should be considered on employment.     

Sensitization to thimerosal (Merthiolate) is still present today

The results on thimerosal (Merthiolate) hypersensitivity of a retrospective study, together with the relevant data on thimerosal hypersensitivity referred to in the literature up to 1993, are presented. Positive patch test reactions to thimerosal (0.1% pet.) were observed in 32 (1.3%) of 2461 adult patients with suspected contact allergy examined in the period 1987–1992. 20 (0.8%) patients had a solitary positive patch test to thimerosal. The observed incidence is low. Clinical symptoms related to thimerosal hypersensitivity were observed in only 3 patients. The collected results are discussed with emphasis on the clinical implications of sensitization to thimerosal. It appears that a positive patch test to thimerosal is frequently clinically irrelevant.