Hand disinfection with short-chain aliphatic alcohols, so-called "rub-ins" is the method of choice for cross-infection prevention in health care environments, but their irritant potential is not well known. Skin tolerance is a major compliance factor, and a high proportion of health care workers suffer from low-grade irritant contact dermatitis. Therefore, assessment of the irritancy of the skin disinfectant n-propanol 60%, and comparative 100% and 0% solutions, was performed in the setting of experimental low-grade ICD. ICD was induced by overnight patch exposure to H2O, and to 0.3% sodium dodecyl sulfate (SDS), in 12 probands, followed by repeated open exposure to the test substances. Outcome variables were transepidermal water loss (TEWL), and skin surface capacitance. On skin sites pre-irritated by SDS, all n-propanol concentrations (100%, 60%, 0%) increased TEWL. However, a clear divergence appeared between pure n-propanol, and the lower concentrations. In contrast to pure n-propanol, n-propanol 60% and 0% had no significant effect on TEWL on H2O-pre-irritated skin sites. Capacitance of pre-irritated skin sites was increased by exposure to H2O-containing n-propanol solutions (60% and 0%). These results show a clear difference between the irritant potential of n-propanol 100% on one side, and n-propanol 60% and 0% on the other side. The level of pre-existent skin irritation is a pertinent factor in susceptibility to irritation, as the irritant potential of n-propanol 60%, the concentration used in daily practice, and n-propanol 0% (water) became significant only on detergent-irritated skin. Thus, preventive skin care may be a constructive approach in increasing tolerance of modern hand disinfection practices.

From February 1989 to January 1990, the Swiss Contact Dermatitis Research Group conducted a 1-year study to examine the frequency of sensitization to a series of 13 common preservatives. A group of 2295 consecutive outpatients with suspected allergic contact dermatitis (age range 7-90 years, with a mean age of 42; 911 males, 1384 females) was tested. The %s of positive reactions to the preservatives studied are as follows, in descending order: formaldehyde 5.7%, benzalkonium chloride 5.5%, Kathon CG 5.5%, thimerosal 4.2%, chlorhexidine digluconate 2.0%, DMDM hydantoin 1.7%, paraben mix 1.7%, chloroacetamide 1.5%, Bronopol 1.2%, imidazolidinyl urea 1.0%, quaternium 15 1.0%, triclosan 0.8%, 2,4-dichlorobenzyl alcohol 0.4%. These relatively high values suggest a heavy exposure of the Swiss population to topical preservatives. Compared to previous studies, the sensitization rate to Kathon CG has stabilized in Switzerland over the last 2 years. Sensitization to formaldehyde portrayed impressive geographical variation, with sensitization rates up to 9% in western and only 3% in eastern Switzerland. The low sensitization rate to parabens argues for their inclusion in a medicament or preservative series, rather than in the standard series.

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Chromotropic acid and acetylacetone methods for qualitative determination of formaldehyde were tested in parallel on 48 commercial samples, with high-performance liquid chromotography (HPLC) implemented for quantitative measure. In addition, interference with the detection of formaldehyde was investigated by analyzing 12 other aldehydes and ketones, 7 essential oils and 3 polysorbates. Throughout this comparative study, the disadvantages of the chromotropic acid method, of which 2 variants were used, were delineated and we found that the acetylacetone test proved to be a more efficient screening method for formaldehyde detection in a clinical laboratory.

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