Validation of Self-testing as a Method to Estimate the Prevalence of Nickel Allergy

The aim of this study was to investigate the validity of self-patch testing for nickel allergy, in order to determine a cost-effective method for surveillance of the prevalence of nickel allergy. Population-based study including patch testing is the most reliable method to study the prevalence of allergy, but it is expensive and has logistical problems. A total of 191 dermatology patients referred to patch testing were provided with a self-test package with written instructions. The self-test was applied on the arm by the patient, on the same day that the regular patch test was applied on the back. The patient evaluated the self-test before patch test reading at the clinic. Patch test at the dermatology clinic detected 46/191 (24%) nickel-positive individuals. The sensitivity of the self-test was 72% (95% confidence interval (Cl) 57-84), the specificity 91% (95% Cl 85-95), and the proportion of agreement 86% (95% CI 81-91). Thus, in the population studied, the validity of self-testing for nickel allergy was adequate

In VivoEvaluation of the Protective Capacity of Different Gloves Against Hair Dyes

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Chemical and Clinical Studies of Isocyanate Contact Allergy with focus on diphenylmethane diisocyanate

Isocyanates are highly reactive compounds used in the production of polyurethane. Exposure to isocyanates is mainly associated with respiratory disorders, but may also result in allergic contact dermatitis. Reports describing contact allergy to isocyanates are few in number and it has been considered a rare phenomenon. In the present study it is shown that the low frequency of reported cases could partly be explained by weaknesses in the method used to detect contact allergy arising from isocyanates, i.e. patch testing with the commercially available isocyanate series. These series generally comprise petrolatum preparations of the four diisocyanates diphenylmethane-4,4'-diisocyanate (4,4'-MDI), 2,4-toluene diisocyanate (2,4-TDI), 1,6-hexamethylene diisocyanate (1,6-HDI) and isophorone diisocyanate (IPDI), as well as two corresponding amines, 4,4'-diaminodiphenylmethane (4,4'-MDA) and isophorone diamine (IPDA). The following results are reported in the thesis. (i) Chemical analyses of isocyanate series obtained from four American and nine European patch testing departments showed that patch test preparations of 2,4-TDI, 1,6-HDI and IPDI contained the declared concentrations, but the concentration of 4,4'-MDI was generally so low that patch testing with it could not be considered reliable. (ii) A stability study showed that preparations of technical grade MDI, i.e. polymeric MDI (PMDI), were more stable and more homogeneous than preparations of pure 4,4'-MDI during the course of a year. (iii) A patch test study revealed that PMDIs rendered as many positive reactions as 4,4'-MDI, (iv) that positive reactions to 4,4'-MDI and PMDI appear late, i.e. after day 3 and sometimes also after day 7, and (v) that the amine 4,4'-MDA is a good marker for 4,4'-MDI contact allergy. In order to optimize patch testing with isocyanates it is thus recommended that patients be tested with their own work products containing technical grade isocyanates since they better reflect the possible allergens that patients are in fact exposed to. It is not yet known if the isomers presently used in commercial preparations are the most potent allergens in technical grade products or if there are other monomers and/or oligomers that cause skin problems. When contact allergy to MDI is suspected patients can also be tested with 4,4'-MDA since it is a marker for 4,4'-MDI contact allergy. Isocyanate patch tests should be read on day 3 or 4 as well as on day 7

Variation in the amount of petrolatum preparation applied at patch testing.

The elicitation of a positive patch test reaction in a given individual depends upon the dose of the sensitizer applied, the patch test technique and the occlusion time. The dose is determined by the concentration and volume/amount of test preparation applied. If the same amount/volume of a test preparation is applied all the time with the same test technique (same area of skin) and occlusion time, it is appropriate to use concentration as a dose parameter. Most contact sensitizers are incorporated in petrolatum (pet.). With pet. as vehicle, it is impossible to repeatedly apply an exact volume/amount. This study was performed to investigate the inter- and intra-individual variation of pet. preparation applied at patch testing by 3 technicians. Weighing demonstrated that the 3 technicians had about the same precision in their pet. application. The investigation demonstrates that there is both an inter-individual (statistically significant) and intra-individual variation in the amounts of pet. applied at patch testing for the 3 technicians. Presently, there is no recommendation on what amount of pet. preparation to apply, which merits a decision to be taken based on thorough investigations on the appropriate volumes of pet. preparation to be applied in various patch test systems

Clinical relevance of positive patch test reactions to lanolin : A ROAT study

Background: Lanolin is often included when patch testing for common contact allergens. The clinical relevance of a positive patch test reaction to lanolin markers is, however, still a subject for debate. Objectives: To evaluate Amerchol L101 as a marker of lanolin allergy and investigate the clinical impact of lanolin-containing moisturizers on healthy and damaged skin using the repeated open application test (ROAT). Methods: Twelve test subjects and 14 controls were patch tested with Amerchol L 101 and additional lanolin markers. Subsequently, a blinded ROAT was performed on the arms of the study participants for 4 weeks. Each participant applied a lanolin-free cream base and two different lanolin-containing test creams twice daily on one arm with intact skin and on the other arm with irritant dermatitis, induced by sodium lauryl sulfate (SLS). Results: Eleven test subjects (92%) had positive patch test reactions to Amerchol L 101 when retested and one test subject (8%) had a doubtful reaction. None of the study participants had any skin reactions to the ROAT on intact skin and all participants healed during the ROAT on damaged skin. Conclusions: Lanolin-containing emollients do not cause or worsen existing dermatitis when performing ROAT in volunteers patch test positive to Amerchol L101

Textile contact dermatitis: how fabrics can induce dermatitis

Purpose of the review Textile dermatitis can sometimes be difficult to diagnose due to the fact that it is difficult to clinically suspect, and when allergic, patch test correctly and advice the patient as to what garments to avoid. Recent findings The textile fibres as such are rarely the causative agent. Allergic contact dermatitis due to textiles is primarily caused by substances that are used to give the material certain qualities or performances. The textile dye mix, now in the baseline series, has proven to be a useful tool in diagnosing allergic contact dermatitis but additional patch testing with own material is advocated. Future research will hopefully facilitate the diagnostic procedure. Summary This review is a short update on textile dermatitis, both irritant and allergic, the present recommendations regarding patch testing when suspecting contact allergy and the advice to give to those allergic that will hopefully help the clinician in daily work