Allergic contact dermatitis from para-chloro-meta-xylenol in Lurosep soap

Allergic contact dermatitis to chloroxylenol

Chloroxylenol, also known as p-chloro-m-xylenol (PCMX), is a compound that has been used as a preservative in cosmetics and as an active agent in antimicrobial soaps. We present two patients with allergic contact dermatitis from PCMX, confirmed by positive (+++) patch-test reactions at 48 and 72 hours, identification of PCMX in a soap and in a hand cream used by the patients, and improvement following withdrawal of the incriminating products. The mechanism of action, structure, antimicrobial activity, and dangers of PCMX are reviewed.

Allergenicity evaluation of p-chloro-m-cresol and p-chloro-m-xylenol by non-radioactive murine local lymph-node assay and multiple-dose guinea pig maximization test

p-Chloro-m-cresol (PCMC) and p-chloro-m-xylenol (PCMX) are known to cause allergic contact dermatitis. For risk assessment of skin sensitizers, information on dose-response profiles in the induction and elicitation phases and cross-reactivity with analogous chemicals are important. In the non-radioactive local lymph-node assay (LLNA) using 5-bromo-2'-deoxyuridine instead of 3H-methyl thymidine, significant effect on lymph node cell proliferation was detected at 10% PCMC and 25% PCMX, while in the multiple-dose guinea pig maximization test (GPMT) at least one animal tested in the group was sensitized at a 5 ppm induction dose of either chemical. When mean skin reaction score in an animal group maximally sensitized with each allergen with the GPMT was plotted against log challenge concentration, linear regression lines with high correlations were obtained in both cases. The calculated elicitation threshold was lower for PCMC than PCMX. The area under the linear regression line between the threshold point and 1% of the elicitation concentration, another index of relative elicitation potency, was also greater for PCMC. Bidirectional cross-reactivity between PCMX and PCMC was detected in the GPMT. PCMC was thus identified in both LLNA and GPMT as a stronger sensitizer than PCMX in both the induction and elicitation phases. These results suggest that the non-radioactive LLNA is a simple and useful method for evaluating allergenicity in the induction phase, while the GPMT using a maximally sensitized animal group is more suitable for assessing the dose-response profile and cross-reactivity in the elicitation phase.

The British standard series of contact dermatitis allergens: validation in clinical practice and value for clinical governance

BACKGROUND

All centres use an empirically determined set of 'standard' test allergens for patch testing that contain the commoner environmental sensitizers. Objectives To assess the validity of the British standard series of 12 allergens used in addition to the 23 already in the European standard series.

PATIENTS AND METHODS

Results for 3062 consecutive patients patch tested in seven centres across the United Kingdom during the year 2000 were analysed.

RESULTS

The additional allergens from the British series and positive rates were: methyl dibromoglutaronitrile 2.4%, carba mix 1.6%, tixocortol pivalate 1.5%, ethylenediamine 1.3%, cetearyl alcohol 0.8%, 2-bromo-2-nitropane-1,3-diol 0.8%, diazolidinyl urea 0.7%, chlorocresol 0.6%, budesonide 0.6%, fusidic acid 0.5%, imidazolidinyl urea 0.5%, and chloroxylenol 0.4%. The allergens with the lowest positive rate in the European standard series were primin at 0.6% and isopropyl-phenyl-para-phenylenediamine at 0.4%.

CONCLUSIONS

The 12 allergens in the British series should continue being tested as a standard addition to the European series within the U.K. The collection of data in this manner to allow comparisons between centres shows differences that reflect selection criteria and interpretation of results, and offers a useful tool for audit and clinical governance. Testing fewer than 1 : 2150 population may indicate underprovision of service. Similarly, rates of sensitization for nickel contact allergy above 26% and for fragrance mix above 16% (the upper 95% confidence intervals) should stimulate inquiry into the reasons behind this.

Chloroxylenol and zinc oxide containing cream (Nels cream) vs. 5% benzoyl peroxide cream in the treatment of acne vulgaris. A double-blind, randomized, controlled trial

Forty-one subjects completed a double-blind controlled randomized study comparing the following: (i) Nels cream (containing chloroxylenol and zinc oxide); (ii) 5% benzoyl peroxide cream; and (iii) the vehicle of the Nels cream. Patients applied the medications twice daily for 8 weeks. At the end of the test period there was no significant difference in the reduction of inflammatory and noninflammatory lesion counts achieved by Nels cream and benzoyl peroxide. Both creams proved superior to the vehicle. Efficacy grading by subjects and investigators showed no significant difference between Nels cream and benzoyl peroxide. However, side-effects such as peeling and dryness caused by the treatment were significantly less in the Nels cream group.