Patch testing and contact allergens in Ethiopia – results of 514 contact dermatitis patients using the European baseline series

Background: Patch testing is essential to diagnose allergic contact dermatitis. Dermatologists in many countries use a baseline (standard) series covering the major allergens responsible for allergic contact dermatitis in their population, with the addition of relevant allergens for the individual patient. However, a baseline series has not yet been developed for Ethiopia. Our objective in this study is to identify common contact allergens to form the basis of a future baseline series in Ethiopia. Methodology: We patch tested 514 subjects with dermatitis according to the recommended procedure using the European baseline series for 1 year. Results: 52.7% of the tested subjects showed positive reaction for at least one allergen tested. The top five contact allergens identified were nickel sulfate, fragrance mix I, cobalt chloride, p‐tert‐butylphenolformaldehyde (PTBP) resin and potassium dichromate. Positive reactions to nickel and PTBP were commoner in females. PTBP positivity was strongly associated with foot eczema. Positive test reactions were commoner in cement workers, notably to potassium dichromate, which was also a commoner allergen in patients presenting with hand dermatitis. There were no reactions to several allergens, including neomycin, benzocaine, budesonide, primin and quaternium‐15. Conclusion: Comparable patch test results with other countries have been shown and the European baseline series can be used as a baseline series in Ethiopia with some modification.     

Environmental contact factors in eczema and the results of patch testing Chinese patients with a modified European standard series of allergens

Environmental contact factors in eczema were investigated in China by clinical questionnaire and patch testing patients with a modified European standard series of allergens. 217 consecutive eczema patients were studied. Contact dermatitis (CD) was clinically diagnosed in 30% of the patients. Among the patients patch tested, 46 patients had clinically diagnosed allergic CD (ACD), 20 patients clinically had non-ACD (NACD) (including 16 cases of irritant contact dermatitis, 1 case of phototoxic contact reaction and 3 cases of asteatotic eczema) and 115 patients had clinically suspected ACD. 45 patients (98%) in the ACD group went on to have relevant patch test results. The most common ACD was from metals, fragrance materials, cosmetics and rubber materials. The most common contact allergens identified were nickel, fragrance mix, para-phenylenediamine (PPD), carba mix and thimerosal. No adverse reactions were observed to patch testing, except for pruritus in patch-test-positive patients. The positive rate of patch testing in ACD was much higher than that in NACD (98% versus 15%, P < 0.05, chi(2)-test). 60 (28%) patients had facial dermatitis (FD). Among these, 20 (33%) were confirmed as having ACD. 48 (22%) patients had hand dermatitis (HD). Among these, 7 (15%) were confirmed as having ACD. Fewer patients were confirmed as having ACD in the HD group than in the FD (15% versus 33%, P < 0.05, chi(2)-test). Although the difference was not significant, the total positivity rate in the HD group (55%) was lower than in the other groups. 65 (30%) patients had unclassified endogenous eczema (UEE). The total positive rate of patch testing in the UEE group (56%) was no different from that in the FD or HD groups. However, the relevance of positive patch tests was hard to determine in UEE. These results indicate that CD is common in eczema; relatively more patients with FD have ACD, while other factors, such as irritation, may play more of a role in HD. The total positive rate of patch testing in the UEE group was no different from that in the FD or HD groups, suggesting that patch testing should be stressed in UEE and the relevance of positive patch test results in UEE should be studied further. It is effective and safe to patch eczema patients with a modified European standard series of allergens in China.     

Photopatch testing: recommendations for a European photopatch test baseline series

In order to establish a consensus recommendation for performing photopatch testing, a photopatch test taskforce group was established under the joint umbrella of the European Society for Contact Dermatitis and the European Society for Photodermatology in 2000. After proposing the most adequate methodology in 2004 and completing a European multicentre photopatch test study in 2011, this taskforce is recommending a list of photoallergens that should form part of a baseline series for photopatch testing in Europe. It contains mainly ultraviolet filters and drugs, mostly non‐steroidal anti‐inflammatory drugs. The choice of chemicals was based on the results of a recent multicentre study, previous published cases of photoallergy, and use of the substances in the European market. It is suggested that an extended list of photoallergens should be photopatch tested in selected cases, along with patients' own products. Two contact allergens, cinnamyl alcohol and decyl glucoside, should be simultaneously patch tested in order to clarify photopatch and patch test reactions, respectively, to ketoprofen and methylene bis‐benzotriazolyl tetramethylbutylphenol (Tinosorb M?).     

Results of routine patch testing with corticosteroid series in 2073 patients

The patch test results of 61 patients allergic to at least 1 corticosteroid molecule are presented. These contact allergies were detected by testing with several corticosteroids included in our standard patch test series between February 1988 and December 1990. Whenever possible, further investigations were conducted by means of a more complete corticosteroid series. We found corticosteroids to be the 7th most frequent allergen, positive results being obtained in 2.9% of all patients referred to our contact dermatitis unit. In this series, budesonide was the most common allergen and often gave simultaneous reactions with other corticosteroids.     

Usefulness of the European standard series for patch testing in children A 3-year single-centre study of 337 patients

Results of patch tests in 337 children aged 1 to 15 performed in our paediatric unit during the past 3 years have been analysed retrospectively in order to optimize the patch test series and to assess their relevance. This study represents the most important single-centre study reported so far over a short period. We found a positive patch test rate of 66%, with a peak incidence among children less than 3 years of age (88% versus 58.9%). The most common allergens were metals, especially nickel, fragrances and, less frequently, rubber chemicals. Concerning nickel, positive reactions rarely correlated with a relevant exposure and were difficult to interpret, especially in patients with atopic dermatitis, who are probably more likely to have irritant or false-positive reactions to metals. Based on the results and their relevance, we propose a shortened standard series of patch tests for paediatric patients.     

Proposal for a revised international standard series of patch tests

Worldwide, there are 3 major standard series of patch tests, the European, North American and Japanese, together presenting 32 allergens, the differences between them being the result of regional variation in allergen distribution as well as differences in dermatological opinion. We propose a "minimal" international standard series of 20 allergens, together with an "extended" international standard series of 14 allergens.     

Is the European standard series suitable for patch testing in Riyadh,Saudi Arabia?

Due to the lack of a regional patch test series in our geographical area, the suitability of the European standard series was evaluated by patch testing dermatitis patients in Riyadh, Saudi Arabia. Of 240 consecutive patients with various forms of dermatitis, 136 (57%) showed 1 or more positive patch tests, women, 74 (54%), slightly outnumbering men, 62 (46%), Positive reactions were found to 21 of the 22 items in the test series. Sensitization was most common to nickel sulfate (51=37.5%), potassium dichromate (48=35%) and cobalt chloride (43 = 32%). The frequency of sensitization to nickel was higher in women (41=30%) while that to dichromate was higher in men (39=29%). Less reactions were found to fragrance mix (21 = 15%). formaldehyde (15=11%) and neomycin sulfate (15=11%). Sensitization to other allergens ranged between 10 and 1%. Less than 1% of patients (0.7%) reacted to benzocaine and none to primin. The frequency of occurrence of multiple sensitivities is also presented. We conclude that the European standard series is suitable for patch testing dermatitis patients in our region, with the exception of benzocaine and primin. The addition of 3 allergens that could be of local relevance is discussed.     

Metal patch testing in patients with oral symptoms

The number of patients with metal allergies has increased recently, and patch testing is useful for investigating such patients. However, the efficacy of restoration removal in patients with oral metal allergies is disputed. This study aimed to investigate the relationships between oral symptoms and metal allergies. We conducted a retrospective analysis of 60 patients with oral symptoms. The most common oral symptom was an abnormal oral sensation. Thirty‐eight percent of the patients exhibited positive allergic reactions to one or more metal. Nickel was the metal allergen that produced positive reactions most frequently. Of the seven patients whose restorations were removed, complete and partial remission were achieved in one and two patients, respectively. Interestingly, metal alloy removal was effective in 33% (n = 1) of the positive patch test group and 50% (n = 2) of the non‐positive patch test group. Our results demonstrated the difficulty of predicting the efficacy of restoration removal at ameliorating oral metal allergies based on patch testing alone.     

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.     

Survey of patch testing in Scotland

We have surveyed Scottish dermatologists to establish the extent of patch testing, to assess the reasons for referral and to document resources and methods used by dermatologists. 104 questionnaires were sent to members of the Scottish Dermatological Society. 82 questionnaires (79%) were returned. 50% of respondents were consultants, 27% were trainees and 23% held staff grade or clinical assistant positions. The mean waiting time for a patch test appointment was 4.5 months. The most frequent reasons for patch testing were localized eczema, eczema not responding to conventional treatment, occupational eczema, history of contact sensitivity and eczema of uncertain cause. 17 of 82 respondents (21%) were the principal clinicians supervising patch testing in their hospitals. 11 of 17 read reactions at 2 and 4 days. Mean time spent on advising patients was 13 min per patients. 7 of 17 were dissatisfied with resources available for patient education and 16 of 17 felt they would benefit from a central source for patient information. Only 4 of 17 centres recorded patch test results on a database and 3 centres regularly reviewed their patch test results. In conclusion, we have identified areas of patch testing that require further improvement.     

Current patch test results with the European baseline series and extensions to it from the 'European Surveillance System on Contact Allergy' network, 2007-2008

Background. The pattern of contact sensitization to the supposedly most important allergens assembled in the baseline series differs between countries, presumably at least partly because of exposure differences. Objectives. To describe the prevalence of contact sensitization to allergens tested in consecutive patients in the years 2007 and 2008, and to discuss possible differences. Methods. Data from the 39 departments in 11 European countries comprising the European Surveillance System on Contact Allergy network ( www.essca‐dc.org ) in this period have been pooled and analysed according to common standards. Results. Patch test results with the European baseline series, and country‐specific or department‐specific additions to it, obtained in 25 181 patients, showed marked international variation. Metals and fragrances are still the most frequent allergens across Europe. Some allergens tested nationally may be useful future additions to the European baseline series, for example methylisothiazolinone, whereas a few long‐term components of the European baseline series, namely primin and clioquinol, no longer warrant routine testing. Conclusions. The present analysis points to ‘excess’ prevalences of specific contact sensitization in some countries, although interpretation must be cautious if only few, and possibly specialized, centres are representing one country. A comparison as presented may help to target in‐depth research into possible causes of ‘excess’ exposure, and/or consideration of methodological issues, including modifications to the baseline series.