A new patient education approach in contact allergic dermatitis: the Contact Allergen Replacement Database (CARD)

BACKGROUND: When a patient is identified by patch testing as being sensitive to a specific contact allergen, he or she is generally advised to read the product labels and avoid products that contain the specific allergen. Patients are often confronted with difficult chemical names, synonyms, and cross-reactants for individual allergens. At the same time, dermatologists may spend a considerable amount of time trying to educate their patients about the avoidance of these allergens and explaining which products may contain them. METHODS: We applied a new educational approach to inform patients about products that are free of their allergens. RESULTS: We present a patient with multiple contact allergens in whom the Contact Allergen Replacement Database was used to educate about specific allergens. This approach has proved to be an invaluable tool for both physicians and their patients in contact allergy counseling.     

Updating the British Society for Cutaneous Allergy Facial Series to ensure accurate diagnosis of allergic contact dermatitis

Allergic contact dermatitis (ACD) is a localised form of dermatitis or eczema which occurs 48‐72 hours after a substance which causes allergy (an allergen) has been in contact with the skin. It affects 20% of people. ACD to cosmetics is widely reported, with facial eczema being the main presenting complaint. ACD to cosmetics is diagnosed by patch testing to the British Society of Cutaneous Allergy (BSCA) facial series. Patch testing is a specialist test performed by a dermatologist which involves applying a series of allergens to the patient’s back, which remains in place for 48 hours until they are removed. The patient then returns, 72 hours after the initial application of the allergens, for the final readings to see if they have any positive allergic reactions. To ensure we are accurately diagnosing ACD, patch test series should be continually reviewed to identify relevant and emerging allergens and remove those that are outdated. The BSCA facial series currently recommends 26 allergens and was last modified in 2012. We set out to update the BSCA facial series. We assessed the results from 12 U.K. and Ireland patch test centres’, facial series from January 2016 to December 2017. We recorded the number of allergens tested in each centre and calculated the patch test rate for each allergen, using a 0.3% positive patch test rate as the threshold criterion for inclusion. A total of 4224 patients were patch tested to the BSCA facial series. The number of allergens included in individual centres facial series ranged from 24 to 66 with a total of 103 allergens tested across all centres. Twelve of the 26 allergens in the BSCA facial series had a positive patch test rate of less than 0.3% and 14 had a rate more than 0.3%. Twenty‐five allergens not recommended in the BSCA facial series had a positive patch test rate more than 0.3%. Despite a recommended facial series, there is wide variation in practice amongst patch test centres. Using our results, we have updated the BSCA facial series which now contains 24 allergens. Fifteen allergens remain, 11 allergens have been dropped and nine new allergens have been added. Linked Article:   Rolls et al. Br J Dermatol 2021; 184 :151–155 .     

Patch test results may vary depending on where testing is performed: a comparison of patch test results from three geographically distinct sites in the USA

Background Do patch test results vary from one part of the USA to another? Few reports directly compare the results of patch testing across centers within the USA. Objectives Our objective was to compare results of patch testing from three geographically disparate Mayo Clinic sites in the USA to ascertain whether there are any differences in allergic patch test rates. Methods We retrospectively reviewed patch test results for patients tested with a standard allergen series using our enterprise‐wide protocol for patch testing. We compared data collected from January 1, 2001, through to December 31, 2007, from our practice sites in the Midwest, Southwest, and Southeast regions of the USA. Results In total, 5063 patients underwent patch testing. The mean (standard deviation) number of allergens tested per patient was 70.3 (3.8) (range: 10–87; interquartile range: 68–73). Analyses were conducted separately for 72 allergens with positive reactions from at least 20 patients. Risk‐adjusted positive reaction rates (RAPRRs) for 44 allergens differed significantly (P < 0.05) among the geographic sites; RAPRRs differed significantly across all three sites for 11 allergens and between two of the three sites for 33 allergens. Conclusions Allergic patch test rates differed among our three practice sites for many allergens. It is likely that many factors contributed to these observed differences, including variations in the population undergoing patch testing, variations in allergen exposure, and variations in climate.     

Patch testing with a combination of unrelated allergens: a new strategy

Summary A simplified method of patch testing was designed, in which several totally unrelated allergens were combined in each patch. The method was evaluated by double blind comparison of responses to 17 standard allergens applied individually as 17 conventional patch tests, and as two different sets of five patches each containing combinations of three or four allergens per patch, in 137 patients under investigation for contact allergic dermatitis. There were 89 positive responses to conventional patch testing with separate allergens and 94 and 86 positives to the two different combinations of the same allergens. Concordance of positive reactions to the two combinations was 80% and there were no irritant reactions. Conventional testing detected 70 and 74% of reactions to combination patches 1 and 2 and combination patches 1 and 2 detected 80 and 79% of the reactions to conventional testing. The combinations detected clinically relevant sensitivities not found by conventional testing. Thus, combination patch testing appears to give consistent and reliable results; its use would reduce the number of patches and increase the diagnostic yield for the specialist and permit preliminary screening by the general practitioner.     

Patch testing with pure palladium metal in patients with sensitivity to palladium chloride

During a 15-month period, 536 patients being investigated for suspected contact dermatitis were patch tested with the European standard series and palladium chloride 1% pet. 13 patients (2.4%) had a positive allergic response to palladium chloride and all 13 were also allergic to nickel. 12 of these 13 patients consented to further patch testing with discs of pure palladium metal foil, and none reacted. We have shown previously that palladium chloride patch test material contains traces of nickel, and propose an explanation for these results in terms of the additive effect of allergens when tested in combination.     

The detection of clinically relevant contact allergens with a standard screening tray of 28 allergens

Background. A standard method for diagnosing allergic contact dermatitis in the United States is the Thin‐layer Rapid Use Epicutaneous (TRUE) test (TRUE Test?), which consists of three panels containing 20 individual allergens and eight allergen mixes. Previous studies had raised concern regarding the adequacy of the initial two‐panel TRUE Test? system (16 individual allergens and seven allergen mixes) in fully assessing patients with possible allergic contact dermatitis. Objectives. We sought to investigate the effectiveness of the current three‐panel TRUE Test? as the sole diagnostic tool for detecting allergic contact dermatitis. Patients/materials/methods. This study was a retrospective analysis of 2088 patients who underwent patch testing between 1995 and 2010. Study groups were analysed to determine whether positive reactions were to allergens and/or mixes present in the TRUE Test? panels. Results. Of the 2088 patch‐tested patients, 1385 had at least one positive reaction. Among these 1385 patients, 27.6% were fully evaluated by use of only the TRUE Test? series, 49.9% were partially evaluated, and 22.5% did not have any of their allergens detected. On assessment for clinical relevance, similar percentages were observed. Conclusion. In our study, the current TRUE Test? series of 28 allergens would have completely identified allergens in only 27.6% of patients. Broadening the standard panel to include common allergens causing >50% of allergic contact dermatitis cases in a given geographical location and aim testing allergens on the basis of the patient's history will increase the test's sensitivity.     

How well is the outcome of patch testing remembered by the patients? A 10‐year follow‐up of testing with the Swedish baseline series at the Department of Dermatology in Örebro,Sweden

Background. Patch testing is beneficial for patients with contact dermatitis. However, it is not known how well the outcome of patch testing is remembered after a prolonged period. Objectives. To study how well patients remember the outcome of their tests after 1–10 years. Patients/materials/methods. In 2010, a questionnaire was sent to all patients tested with the Swedish baseline series in 2009, 2005, and 2000. Results. The response rate was 53.3% (252/473), and 96% (241/252) of patients reported that they had been submitted for allergy testing. Among those with positive patch test results, 79% (111/141) remembered a positive result and 29% (41/141) reported the correct name of the allergen. We found a wide variation (0–80%) in how well the patients remembered positive test results for different allergens. The ability to recall allergens had no relationship with the localization or extension of eczema lesions, but was negatively correlated with the number of diagnosed allergies, the number of years after patch testing, and being male. Conclusions. Our results indicate that improved information for patients following patch testing is required, in order to improve the prognosis of contact dermatitis.     

Allergic contact dermatitis to indium in jewellery: diagnosis made possible through the use of the Contact Allergen Bank Australia

We report a case of a 39‐year‐old woman from Adelaide who developed allergic contact dermatitis to the rare allergen indium in her ring. The allergen was sourced for patch testing using the Contact Allergen Bank Australia (CABA), based at the Skin and Cancer Foundation in Melbourne, and posted to Adelaide. This case illustrates the usefulness of CABA in facilitating patch testing throughout Australia, especially when rare allergens are involved.     

Allergy to lanolin

The purpose of the present study was to compare the frequency of lanolin allergy during two periods and to assess the adequacy of testing with one standard allergen. Among 1230 consecutive patients with eczema who were standard patch tested, 33 (2.7%), 21 females and 12 males, gave a positive reaction to wool alcohols. Among 899 consecutive patients with eczema standard patch testd and also tested with the lanolin derivatives hydrogenated lanolin 30% in soft yellow paraffin, Amerchol L 101, and a mixture of lanolin derivatives, 60 patients (6.6%), 48 females and 12 males, gave a positive reaction to lanolin and/or its derivatives. The results show that testing with one standard lanolin allergen is inadequate for detecting lanolin allergy.     

The additive value of patch testing with patients' own products at an occupational dermatology clinic

Background and objectives: Patch testing with commercially available kits detects only 70–80% of relevant allergens in patients with contact dermatitis. This is not ideal, especially when occupational issues are being evaluated. This study analyses our data regarding reactions to patients' own products.
Methods: In a 5-year period, 1532 patients were assessed in our occupational dermatology clinic.
Results: We found that 101 patients (6.6%) reacted to their own samples. In 20 (1.3%) cases, reacting to their own samples was the only clue for detecting the responsible allergen. In 59 (3.9%) cases, testing with their own samples reinforced their reactions to commercial allergens.
Conclusions: We found the overall additive value of testing with patients' own products to be 5.2%. This is not a low proportion considering the 20–30% false negative rate when patch testing. Patch testing with patients' own samples, appropriately diluted should be undertaken whenever possible.     

Positive patch tests with a dermatophagoides mix relate to an increased responsiveness to standard patch test allergens

The diagnostic meaningfulness of patch tests with house dust mite allergens is still questionable. Our own impression has been that positive results with a dermatophagoides mix may occur preferentially in patients with a generally enhanced responsiveness to contact allergens. To check this, all of our patients allocated to patch testing with the standard series were additionally patch tested with a dermatophagoides mix by the same technique that was used for standard contact allergens. Out of 571 patients tested, 188 showed delayed responses to this mix that were indistinguishable from typical allergic patch test reactions but of no apparent clinical relevance. No relationship was found between positive dermatophagoides patch tests and an atopic disposition of the patients or characteristics of their eczema. However, 64.4% of the patients with a positive dermatophagoides patch test showed a response to at least 1 contact allergen of the standard series, compared to only 56.4% of the patients without a positive dermatophagoides reaction (p < 0.05). The reactivity to the mite mix was not related to the responsiveness towards any particular contact allergens. We suppose that some unidentified factors may contribute to positive reactions to the dermatophagoides mix that may also favour an enhanced general responsiveness to contact allergens.     

Patch test reaction on Ethiopian subjects with eczema

Background  Allergic contact dermatitis is a common condition with an incidence of 1–10% in the general population. An increasing number of allergens in the environment are responsible for the condition. These allergens can be identified using patch testing. Many countries have a standard series of common allergens used for patch testing. There is no standard series of allergens in Ethiopia, and our objective was to obtain baseline data for common allergens for future standardization.
Methods  One hundred and eighty-one subjects with eczema were patch tested using 17 selected allergens from Chemotechnique Diagnostics AB employing a standard procedure.
Results  Positive patch test reactions were detected in more than 60% of subjects, the most common allergen being nickel, followed by fragrance mix and butylphenolformaldehyde. A higher incidence of positive reactions was seen in females.
Conclusions  A high incidence of positive patch test reactions was identified in the study population, and the introduction of patch testing in Ethiopia is essential for the management of allergic contact dermatitis.     

干扰素局部注射和外用药物治疗扁平疣40例疗效观察

目的观察重组人干扰素α-1b局部注射治疗扁平疣的疗效。方法将76例扁平疣患儿随机分为两组,治疗组40例,给予皮损内局部注射重组人干扰素注射液α-1b,每周1次;对照组36例,皮损给予0.1%维A酸软膏和重组人干扰素α-1b凝胶外用。疗程28天。随访6个月。结果治疗组总有效率90.00%,对照组总有效率63.89%。治疗组疗效好于对照组（P〈0.01）。结论重组人干扰素α-1b局部注射治疗扁平疣疗效确切。     

'Irritants' increase the response to an allergen in allergic contact dermatitis

We studied the effect of "irritants" on the response to an allergen in 15 patients. Dilutions of allergens were applied in duplicate, and 24 hours later they were removed and sodium lauryl sulfate (11 subjects) or anthralin (dithranol) (four subjects) was applied for a further 24 hours to one set of patches. Control dilutions of irritants alone were applied. Responses were measured objectively at 72 hours. The response to both allergen and irritant was greater than to either alone. Doses of allergen, which did not produce a response when applied alone, produced a response when an irritant was added. Irritants therefore increase the allergic contact dermatitis response and may explain the presence of contact dermatitis in patients with negative patch tests.     

Polysensitisation in a laboratory scientist associated with allergic contact dermatitis from methylisothiazolinone in skin cleansers

Polysensitisation refers to reactivity to three or more allergens on epicutaneous patch testing, and is likely to affect a distinct subgroup of individuals with allergic contact dermatitis (ACD). Methylisothiazolinone (MIT) is an increasingly prevalent allergen, recently having been described as occurring in epidemic proportions. We report a patient with ACD to 12 allergens, including MIT, and discuss the implications of polysensitisation and the likely need for repeat patch testing in such patients if they subsequently re‐present with dermatitis.     

南京地区斑贴变应原种类的初步筛选

目的：筛选南京地区的斑贴变应原种类。方法参照曲泰斯及国际接触性皮炎研究组提供的标准,并以前期文献分析数据为依据,制备40种斑贴变应原。纳入443例接触性皮炎（湿疹）患者,先后给予曲泰斯和自制斑试变应原检测,观察两组斑试变应原在患者中阳性率差异,以评估在临床应用的可行性。结果：自制斑试变应原总体阳性率低于曲泰斯（73% & 81.7%）,二者差异具有统计学意义（P＜0.05）;相同的斑试变应原相比,12种自制斑贴试剂单个变应原检测阳性率低于曲泰斯;除常规检测的24种斑贴变应原外,另外检测到16种阳性率较高斑贴变应原,也是南京地区常见的接触过敏原。结论：除曲泰斯标准变应原系列提及的24种变应原外,另16种阳性率较高的变应原可同时纳入南京地区筛选抗原系列。      

Patch test reactions at D4, D5 and D6

In this retrospective study, patch test reactions in 3 groups of patients were analysed, in order to obtain information on the best day for the 2nd patch-test reading after day 2 (D2), on the usefulness of additional readings after D3, and on the dependence of patch-test reactions at D4, D5, or D6 on allergen and/or patient characteristics. In the years 1990 to 1995, patch tests were routinely read at D3 and D4 in 1096 patients, at D3 and D5 in 1243 patients, and at D3 and D6 in 1136 patients. In all of the 3 groups, significantly more positive reactions diminished than appeared de novo from D3 to the later reading. Virtually identical results were observed in subgroups of patients formed by sex, age or atopy. However, men might possibly react more slowly than women on patch testing, showing more increasing than diminishing reactions in the D3/D4- and the D3/D5-comparison. Reactions to individual allergens showed wide differences in this connection. Neomycin sulfate, cobalt salts, and p-phenylenediamine can be characterized as slow allergens, with more reactions increasing than diminishing from D3 to the later readings. With fragrance mix and balsam of Peru, the opposite pattern occurred. In all subgroups of patients, and with most allergens, the gain in positive reactions was biggest when an additional reading was performed at D5. We conclude that for a single 2nd patch test reading after D2, D3 is the best day, and especially better than D4. If a 3rd reading is performed, it should be done at D5 to get the maximum information out of patch testing. However, this extends the test procedure to at least 1 day of the weekend.     

Atopy patch test reaction to airborne allergens in the diagnosis of atopic dermatitis

The aim of the study was to evaluate the possible use of atopy patch test in the diagnosis of atopic dermatitis and to characterize an optimal standardized system for atopy patch test in terms of allergen concentrations and time of allergen exposure. The study included 36 patients with atopic dermatitis and IgE-mediated airborne allergy. Patients presented positive results of skin prick tests and serum antigen specific IgE against house dust mite allergens and/or selected grass pollen allergens. Control groups consisted either of patients with allergic rhinitis (control group 1) or healthy volunteers with no signs or symptoms of atopy (control group 2). Allergologic diagnostic workup consisted of skin prick test, serum antigen specific IgE and total IgE evaluation, atopy patch test with selected airborne allergens of different concentrations (0.1xSPT, 1xSPT and 10xSPT), time of allergen exposure (8, 24 and 48 h), and readings of the results (8, 24, 48 and 72 h). Positive results of atopy patch test with airborne allergens were obtained in 47.2% of atopic dermatitis patients and none of control subjects. Contact reaction itself and the intensity of reaction were demonstrated to correlate with allergen concentration and time of allergen exposure on atopy patch test. The dose and time response analysis showed the optimal concentration of allergens for atopy patch test to be 10xSPT, 500000 SBE/ml, and optimal evaluation time 24 and 48 h of allergen application. There was no correlation between atopy patch test results and mean serum concentrations of total or antigen specific IgE. Atopy patch test results did not correlate with localization of skin lesions, severity and extensiveness of skin inflammation. A significantly higher contact reactivity to airborne allergens was recorded in the group of atopic dermatitis patients with polyvalent allergy in comparison with atopic dermatitis patients allergic to only one aeroallergen. It is concluded that atopy patch test is the only provocation test currently available with clinical relevance for contact IgE-mediated sensitization in atopic dermatitis patients. Using petrolatum as a vehicle, allergen concentration of 500000 SBE/ml and evaluation time of 24 and 48 h of allergen application may lead to improved atopy patch test results.     

The reproducibility of patch tests

There is conflicting evidence regarding the reproducibility of patch testing. Discordant results have been reported in up to 44% of cases. The clinical relevance of these discordant patch tests has not been previously assessed. We studied 383 consecutive patients receiving simultaneous duplicate patch testing on opposite sides of the upper back with 10 allergens from the European standard series. Completely discordant patch tests-a negative test on one side with a positive test on the opposite side-were recorded in 30 (8%) patients. Two patients had discordant tests to two of the allergens; 28 had discordant reactions to one allergen. Completely discordant tests were recorded for nickel in 10 (3%) patients, balsam of Peru in two (0.5%), thiomersal in one (0.3%), cobalt in four (1%), paraphenylenediamine in three (0.8%), fragrance mix in two (0.5%), formaldehyde in four (1%), potassium dichromate in two (0.5%), lanolin in three (0.8%) and Kathon CG in one (0.3%). Of those patients with completely discordant patch tests, the allergen was deemed to be a true positive in 11 (3% of total) cases and of possible relevance in a further three. The allergen was felt to be relevant to the presenting complaint in seven (2% of total) patients.     

Pruebas epicutáneas en pacientes con eczema perianal

Introduction and objectivesReports show that between 25% and 78% of patients with anogenital dermatitis have positive patch test results. Consequently, patch testing would appear to be warranted in patients presenting with eczema in the anogenital region. The objectives of the present study were to identify the most common allergens in patients with perianal eczema and to determine which allergen series are most useful for patch testing in patients with this condition.Material and methodsWe performed a retrospective review of patch test results in patients with only perianal eczema between 2001 and 2012.ResultsOf the 37 patients with perianal eczema, 16 had a positive reaction; methylchloroisothiazolinone/methylisothiazolinone was the main allergen involved. With the exception of 1 case of sensitization to gentamicin, all the positive results with present relevance were to allergens from the standard series of the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC) or to the patient's own products.ConclusionsIn our experience, methylchloroisothiazolinone/methylisothiazolinone is the main allergen involved in perianal eczema, and sensitization often results from using wet wipes. Patch testing in perianal eczema should be based on the GEIDAC standard series and the patient's own products.