Thiuram Mix Research Articles

Differential Diagnosis of Irritant Versus Allergic Contact Dermatitis Based on Noninvasive Methods

Introduction: Irritant contact dermatitis (ICD) is characterized by direct injury to the epidermal cells, activating the innate immune response. Allergic contact dermatitis (ACD), in contrast, is delineated by a delayed hypersensitivity reaction of type IV. Despite the distinct etiopathogenic mechanisms underpinning each condition, the differentiation between them presents a significant diagnostic challenge. Objective: This study aims to determine whether a combination of clinical evaluation and noninvasive measurements—encompassing oxidative stress, erythema, hydration, melanin content, transepidermal water loss (TEWL), hemoglobin concentration, and skin texture and volume—can distinguish ICD from ACD. Methods: Two cohorts, each comprising 21 patients, were evaluated: one diagnosed with ICD and the other with ACD. All participants underwent biophysical and clinical assessments, along with Antera® 3D evaluations. Tape strips were utilized for skin sampling, and oxidative stress levels were measured via fluorescence assessments. Results: ICD prompts an almost immediate inflammatory reaction (peaking at 24 hours), whereas ACD incites a delayed response (72 hours). Noninvasive evaluated parameters as hemoglobin concentration, skin texture and volume, melanin content, erythema, and TEWL showed significant differences between the ICD and ACD cohorts (p < 0.05). The allergens amcinonide, nickel sulphate, cobalt chloride, budesonide, PPD, and thiuram mix were found to induce elevated levels of oxidative stress. Conclusions: The evaluation of patients with noninvasive parameters, including transepidermal water loss (TEWL), hemoglobin concentration, and skin texture and volume, could markedly aid in distinguishing irritant contact dermatitis from allergic contact dermatitis (ACD). Nevertheless, the study is constrained by a limited sample size.

Allergens causing contact dermatitis of the feet: Investigation and analysis of allergic reaction causes.

Allergic contact dermatitis of the feet is a significant problem that affects the quality of life and requires attention from the medical community due to the number of studied and still unidentified allergens. The purpose of this review article is to summarize the available scientific data regarding the most common allergens that cause ACD of the feet. Nickel sulphate, neomycin sulphate, thiuram mix and colophony occupy a significant place in the prevalence of allergies. The prevalence of sensitization to rubber and leather products can vary depending on the ethno-demographic characteristics of the country, as well as the specifics of a person's professional activity, such as the use of protective waterproof shoes, increased humidity of the microclimate, and atopy in anamnesis. Patch testing has been shown to be an important method for identifying allergens, however, not all footwear components are tested during patch testing with standard allergen series, requiring the use of patches made from patient shoe samples. Expanding the scope of patch testing to include other possible allergens is important for the accurate diagnosis of ACD of the feet and a more detailed study of those allergens that were previously considered rare.

Occupational Contact Dermatitis in Construction Workers: A Retrospective Analysis of the North American Contact Dermatitis Group Data, 2001-2020.

Background: Construction workers (CWs) are at risk for occupational contact dermatitis (CD) owing to workplace exposures. Objective: Determine the prevalence of occupational allergic CD and characterize common occupational allergens in CWs referred for patch testing in the United States and Canada. Methods: Retrospective cross-sectional analysis of patients patch tested by the North American Contact Dermatitis Group from 2001 to 2020. Results: Of 47,843 patch-tested patients, 681 (1.4%) were CWs. Compared with non-CWs, CWs were more likely to be male (91.0% vs 30.9%) have occupational skin disease (36.9% vs 11.4%) and have hand involvement (37.2% vs 22.5%) (all P < 0.0001). Of 681 CWs, 60.1% (411) had clinically relevant positive patch test reactions, and nearly 1/3 of CWs (128) had occupationally relevant reactions. Most common occupationally relevant allergens were potassium dichromate 0.25% pet. (30.5%, 39/128), bisphenol A epoxy resin 1% pet. (28.1%, 36/128), carba mix 3% pet. (14.8%, 19/128), cobalt (ii) chloride hexahydrate 1% pet. (14.1%, 18/128), and thiuram mix 1% pet. (14.1%, 18/128). Top sources of occupationally relevant allergens were cement/concrete/mortar (20.4%, 46/225), gloves (15.1%, 34/225), and coatings (paint/lacquer/shellac/varnish/stains) (9.8%, 22/225). Conclusions: Occupational CD in North American CWs is common. In this group, frequently identified etiological sources of occupational allergic CD included metals, epoxy resin, and rubber.

Predictive factors of polysensitization to contact allergens: study conducted at the Dermato-Allergology Unit of the Farhat Hached University Hospital in Sousse, Tunisia

polysensitization is often defined as sensitization to three or more contact allergens. The objectives of our study were to determine the prevalence of polysensitization to allergens patch test and to analyze the factors associated with allergen polysensitization of the European Standard Battery in comparison with cases of oligosensitization. this is a retrospective descriptive cross-sectional study that included all patients who had undergone patch tests at the Department of Dermato-Allergology of the Department of Occupational Medicine of University Hospital Center Farhat Hached in Sousse spread over 10 years from January 1, 2009 to December 31, 2018. in total, we collected 464 cases of contact dermatitis during the study period. The average age of patients was 38.93 ± 12.52 years with a slight female predominance (52.8% of cases). Among all the patients who consulted during the study period (832 patients), 133 patients had positive reactions to 3 or more allergens 16% of patients. Concerning, the associations of the most frequently noted allergens were those of triplet (chromium, cobalt, and nickel) in 15 patients and triplet (mercaptobenzothiazole, thiuram mix, and IPPD) in 7 cases. The predictive factors of polysensitivity were the personal history of leg ulcers; the site of the lesions in the thorax and the erythematous squamous and dyshidrotic appearance of the lesions. this phenomenon is frequent polysensitization, and close collaboration between dermatologists and occupational physicians to prevent this type of multiple allergies through better management of personal and also professional risk factors.

Analysis of patch testing results in patients with contact dermatitis in Istanbul, Turkey, from 2012 to 2022.

Allergens responsible for allergic contact dermatitis (ACD) differ between populations. They can even change over the years with the effect of environmental factors. To evaluate the results of patch testing performed in our center. In this study, the thin-layer rapid-use epicutaneous (T.R.U.E.) test results of patients with a diagnosis of ACD between 2012 and 2022 were retrospectively evaluated. In 431 (42.5%) of the total 1012 patients, a positive reaction to at least one allergen was detected in the patch test. Allergen positivity was most detected for nickel sulphate (16.8%), gold sodium thiosulfate (GST) (6.9%), thimerosal (4.2%), fragrance mix (3.4%), carba mix (3.2%), and cobalt dichloride (2.9%). Nickel sulfate and GST sensitivity was found to be significantly higher in women, fragrance mix sensitivity in men, thimerosal sensitivity in individuals aged under 40 years, colophony and balsam of Peru sensitivity in head and neck dermatitis, and carba mix and thiuram mix sensitivity in atopic individuals. This study presents comprehensive data from Turkey concerning the sensitivity frequencies for allergens included in the T.R.U.E. test.

Patch tests and hand eczema: retrospective study in 173 patients and literature review

BackgroundHand eczema (HE) is a highly prevalent, recurrent, and multifactorial disease. It encompasses a group of eczematous diseases that affect the hands, etiologically classified into irritant contact dermatitis (ICD), allergic contact dermatitis (ACD) and atopic dermatitis (AD). Few epidemiological studies in Latin America have investigated the characteristics of patients with this condition and the origin of the disease. ObjectivesTo analyze the profile of patients diagnosed with HE submitted to patch tests aiming to determine its etiology. MethodsA retrospective descriptive study was carried out on epidemiological data and patch tests of patients with HE treated at a tertiary hospital in the city of São Paulo from January 2013 to December 2020. ResultsA total of 173 patients were studied, whose final diagnosis was 61.8% of ICD, 23.1% of ACD and 5.2% of AD, with diagnostic overlap in 42.8% of the cases. The main positive and relevant patch tests were: Kathon CG (42%), nickel sulfate (33%), and thiuram mix (18%). Study limitationsThe number of treated cases and socioeconomic profile was limited to a vulnerable population group. ConclusionHE is a diagnosis in which overlapping etiologies are frequent, with the main sensitizers identified in ACD being Kathon CG, nickel sulfate and thiuram mix.

Patch Testing of Thai Children with Eczema

Objective: To detect contact allergy rate and common allergens in Thai children presented with eczema. Materials and Methods: A total of 124 children, aged 1-15 years, were patch tested using a pediatric screening series of 16 allergens and relevant additional allergens. Data on clinical presentation, atopic history and test results were collected. Results: Contact allergy was found in 51 of 124 children (41.1%) presented with all forms of eczema. The common allergens were lanolin alcohol (8.9%), cocamidopropyl betaine (8.1%), nickel sulfate (7.3%), fragrance mix I (5.6%), formaldehyde (5.6%), thimerosal (5.6%), fragrance mix II (4.8%), cobalt chloride (4.0%), methylchloroisothiazolinone/methylisothiazolinone (2.4%), methylisothiazolinone (2.4%) and thiuram mix (2.4%). Nineteen of 50 atopic dermatitis patients (38%) showed positive patch test reactions. Conclusion: Allergic contact dermatitis is common in children. Both atopic and non-atopic patients can develop contact dermatitis. Patch testing should be performed in children presented with eczema regardless of contact dermatitis history.

Allergic Contact Dermatitis and Patch Testing in Skin of Color Patients.

Objective: Skin of color patients face important health issues relevant to dermatologists, such as allergic contact dermatitis; however, there is a lack of information surrounding common allergens causing contact dermatitis that disproportionately affect skin of color patients, as well as interpreting patch testing in this population. Methods: Covidence, Embase, MEDLINE, PubMed, Web of Science, and Google Scholar were searched to identify relevant articles studying allergic and irritant contact dermatitis in skin of color patients. Results: The most common positive reactions in African American patients included PPD, balsam of Peru, bacitracin, fragrance mix, and nickel. The most common positive reactions in Hispanic patients included Carba mix, nickel sulfate, and thiuram mix. The most common positive reactions in Asian patients included nickel sulfate, fragrance mix, and potassium dichromate. When interpreting patch test results in patients with higher Fitzpatrick skin types, positive patch tests presented with lichenification and hyperpigmentation, rather than erythema and vesicles. Furthermore, characteristic bright red or pink hues for positive results may appear violaceous or faint pink. Conclusions: Awareness of the common allergens associated with allergic contact dermatitis in patients of skin of color can help guide patch testing as an important diagnostic tool. Further research must be conducted regarding contact dermatitis in this patient population, especially given the relative lack of data surrounding Hispanic, Asian and Pacific Islander, and Native American patients.

Pattern of contact sensitization in patients with and without atopic dermatitis in an Asian dermatology center.

Although the traditional understanding is that contact sensitization is less frequent in patients with atopic dermatitis (AD), recent studies have shown similar or higher rates of positive patch-test results in AD patients. We sought to characterise the pattern of contact sensitization in patients with and without AD and evaluate the association between AD and contact sensitization. This was a single-center, 10-year retrospective review of patients who underwent patch testing between 2007 and 2017. There were 4903 patients (male-to-female ratio=1:1.4; mean age 40.1 years) included. About half (2499, 51.0%) of all patients developed at least one positive reaction. The top five frequent reactions were to nickel sulfate (45.4%), potassium dichromate (16.0%), p-phenylenediamine (13.4%), Myroxylon pereirae (11.8%), and fragrance mix I (11.2%). The overall prevalence of contact sensitization was not significantly different between patients with or without AD. Patients with AD were less likely to develop contact allergies to budesonide and thiuram mix, and more likely to develop contact allergies to potassium dichromate. Contact sensitization was detected in 50% of patients who were patch tested. Nickel sulfate was the most frequently sensitizing allergen. The prevalence of contact allergies in atopic patients is comparable to that in non-atopic patients.

Shoe Allergens: A Retrospective Analysis of Cross-sectional Data From the North American Contact Dermatitis Group, 2005-2018.

Shoe contact allergy can be difficult to diagnose and manage. The aim of the study was to characterize demographics, clinical characteristics, patch test results, and occupational data for the North American Contact Dermatitis Group patients with shoe contact allergy. This is a retrospective study of 33,661 patients, patch tested from 2005 to 2018, with a shoe source, foot as 1 of 3 sites of dermatitis, and final primary diagnosis of allergic contact dermatitis. Three hundred fifty-two patients met the inclusion criteria. They were more likely to be male (odds ratio = 3.36, confidence interval = 2.71-4.17) and less likely to be older than 40 years (odds ratio = 0.49, confidence interval = 0.40-0.61) compared with others with positive patch test reactions. The most common relevant North American Contact Dermatitis Group screening allergens were potassium dichromate (29.8%), p-tert-butylphenol formaldehyde resin (20.1%), thiuram mix (13.3%), mixed dialkyl thioureas (12.6%), and carba mix (12%). A total of 29.8% (105/352) had positive patch test reactions to supplemental allergens, and 12.2% (43/352) only had reactions to supplemental allergens. Shoe contact allergy was more common in younger and male patients. Potassium dichromate and p-tert-butylphenol formaldehyde resin were the top shoe allergens. Testing supplemental allergens, personal care products, and shoe components should be part of a comprehensive evaluation of suspected shoe contact allergy.

Occupational Contact Dermatitis in Dental Personnel: A Retrospective Analysis of the North American Contact Dermatitis Group Data, 2001 to 2018.

Dental personnel are at risk of developing occupational contact dermatitis. The aims of the study were to determine prevalence of occupational contact dermatitis in dental personnel referred for patch testing and to characterize relevant allergens and sources. The study used a retrospective, cross-sectional analysis of the North American Contact Dermatitis Group (NACDG) data, 2001-2018. Of 41,109 patients, 585 (1.4%) were dental personnel. Dental personnel were significantly more likely than nondental personnel to be female (75.7% vs 67.4%, P < 0.0001), have occupationally related dermatitis (35.7% vs 11.5%, P < 0.0001), and/or have primary hand involvement (48.6% vs 22.5%, P < 0.0001). More than one quarter of dental personnel (62/585, 27.7%) had 1 or more occupationally related allergic patch test reaction(s). There were 249 occupationally related reactions to NACDG screening allergens, most commonly glutaraldehyde (18.1%), thiuram mix (16.1%), and carba mix (14.1%). The most common sources of NACDG screening allergens were gloves (30.7%), dental materials (26.6%), and sterilizing solutions (13.1%). Seventy-three dental personnel (12.5%) had 1 or more positive patch test reactions to occupationally related allergen(s)/substances not on the screening series. Occupationally related irritant contact dermatitis was identified in 22.2% (n = 130) of dental personnel, most commonly to nonskin soaps/detergents/disinfectants (32.0%). Occupational contact dermatitis is common in dental personnel referred for patch testing. Comprehensive testing beyond screening series is important in these patients.

Occupational contact allergy of construction workers in Greece: Trends during 2009-2018.

Recent trends in the sensitization of construction workers show a decrease in potassium dichromate and an increase in epoxy resin sensitization. To present the trends of occupational contact allergy of construction workers in Greece from 2009 to 2018. We retrospectively reviewed the files of patients with eczema patch tested in our Contact Dermatitis Clinic who were construction workers. A total of 191 construction workers initially reported contact dermatitis. Of these, 138 had occupation-relevant allergic contact dermatitis (ACD) or irritant contact dermatitis (ICD). All patients were men. After being patch tested, 98 (71.0%) were diagnosed with ACD and 40 with ICD. Median duration of occupation till onset of ACD was 2 years (interquartile range [IQR] 0.8-7). The hands were the most common location for ACD (73.5%), followed by the trunk (39.8%), the legs (38.8%), and the face (11.2%). Of the patients, 74.6% had lesions affecting multiple body sites. Potassium dichromate (67%) was the most frequent allergen, followed by thiuram mix (37.4%) and cobalt chloride (31.8%). Sensitization to epoxy resins was lower (12.1%). The sensitization pattern of Greek construction workers does not follow the trends in Central or Northern Europe, rather sharing attributes with less industrialized countries.

Patch testing with expired Indian patch test kits: Results of a pilot study

The reliability of patch testing with expired Indian standard patch test kits has been not evaluated before. Thirty adults (men:women 25:5) with allergic contact dermatitis were divided into three groups of ten patients each for patch testing by Finn chamber® method using Indian standard patch test kits having expiry in 2016, 2015 and 2014. The results were compared with those from a new kit with 2018 expiry. Ten patients in group-1, eight patients in group-2 and seven patients in group-3 developed positive reactions of identical intensities and mostly from identical allergens from all four kits. The major contact allergens eliciting positive reactions of identical intensities were parthenium in nine, five and three patients, colophony in four, one and zero patients, fragrance mix in three, three and one patients, thiuram mix in three, one and one patients, and paraphenylene diamine in two, one and three patients from group-1,-2, and -3, respectively. Small number of patients in each group remains the major limitation of the study. Whether or not these results can be extrapolated with patch test results from other similar patch test kits available across countries also needs confirmation. The patch test allergens can be used beyond labeled expiry dates but needs confirmation by a few large studies and using other available patch test kits. This is important as the relevance of patch test results for individual allergen in this scenario may remain debatable requiring careful interpretation.

Hand eczema in children referred for patch testing: North American Contact Dermatitis Group Data, 2000-2016.

Little is known about the aetiologies and relevant allergens in paediatric patients with hand eczema (HE). To characterize the aetiologies and determine the proportion of positive and currently relevant allergens in children/adolescents (age<18years) with HE referred for patch testing. A retrospective analysis (2000-2016) of North American Contact Dermatitis Group data was performed. Of 1634 paediatric patients, 237 (14·5%) had involvement of the hands. Final physician diagnoses included allergic contact dermatitis (49·4%), atopic dermatitis (37·1%) and irritant contact dermatitis (16·9%). In multivariable logistic regression models, employment was the only association with increased odds of any HE or primary HE. Children with HE vs. those without HE had similar proportions of positive patch tests (56·1% vs. 61·7%; χ2 -test, P=0·11). The five most common currently relevant allergens were nickel, methylisothiazolinone, propylene glycol, decyl glucoside and lanolin. In multivariable logistic regression models of the top 20 relevant allergens, HE was associated with significantly higher odds of currently relevant reactions to lanolin, quaternium-15, Compositae mix, thiuram mix, 2-mercaptobenzathiazole and colophony. The allergens with the highest mean significance-prevalence index number were methylisothiazolinone, carba mix, thiuram mix, nickel and methylchloroisothiazolinone/methylisothiazolinone. Children with HE who were referred for patch testing had a high proportion of positive patch tests, which was similar to the proportion found in children without HE. Children with HE had a distinct and fairly narrow profile of currently relevant allergens.

Patch Test Results to European Baseline Series in Turkey: A Prospective and Multicenter Study.

Patch testing with the European Baseline Series (EBS) is an essential diagnostic tool for the assessment of allergic contact dermatitis. The aims of the study were to describe the most common contact allergens identified with patch testing in Turkey and to establish the distribution of contact allergens among different regions in Turkey. Twelve centers consisting of tertiary health care institutions were included in the study. A total of 1169 patients were patch tested with the EBS from 2015 to 2017. A total of 596 patients (51.0%) had 1 or more positive patch test reactions to the EBS. A total of 30.2% (n = 353) of those tested had clinical relevance. Contact sensitivity was more common in young patients. The most common 10 allergens were nickel sulfate (20.4%), followed by textile dye mix (8.6%), cobalt chloride (8.3%), potassium dichromate (8.0%), p-phenylenediamine base (4.5%), balsam of Peru (4.3%), methylchloroisothiazolinone/methylisothiazolinone (3.8%), thiuram mix (3.6%), fragrance mix I (3.0%), and methylisothiazolinone (2.9%). This study provides a comprehensive profile of patch test results with the EBS in Turkey. An ongoing decrease in contact allergy to methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone was observed. Textile dye mix and p-phenylenediamine are beginning to pose a new risk in Turkey.

Atopic skin diathesis rather than atopic dermatitis is associated with specific contact allergies.

The association of atopic dermatitis (AD) and allergic contact dermatitis has been a matter of considerable uncertainty. Study results range from lack of any association to increased sensitization for multiple allergens, but fail to identify consistent allergen associations. We studied a large patch test cohort of patients stratified by their atopic skin diathesis using the Erlangen Atopy Score (EAS), independent of active skin disease. Retrospective multi-center data analysis from five departments of dermatology in Germany with 4,509 patients. Patients were grouped as "no atopic skin diathesis" (n=2,165) and "atopic skin diathesis" (n=1,743), according to EAS. Significantly more individuals with atopic skin diathesis showed at least one positive patch test reaction to the baseline series compared to individuals without atopic skin diathesis (49.1% vs. 38.3%). In logistic regression analyses, atopic skin diathesis was associated with a significantly higher risk of sensitization to methylchloroisothiazolinone/methylisothiazolinone (OR 2.383) and methylisothiazolinone (OR 1.891), thiuram mix (OR 1.614), as well as nickel (OR 1.530), cobalt (OR 1.683), and chromium (OR 2.089). Atopic skin diathesis proved to be the most important intrinsic risk factor for contact sensitization to few, specific allergens. Past or present AD was a less relevant variable.

Clinical Pattern and Patch Test Profile of Hand Eczema in Hospital Employees in a Tertiary Care Hospital of North India.

Introduction:Health care workers form an important occupational group with a high risk of hand eczema. All health care professionals are exposed to a variety of allergens and irritants which can cause hand dermatitis, resulting in significant morbidity.Aims and Objectives:To assess the clinical profile of hand eczema in hospital employees, to perform patch test in relevant cases and to find out the most common sensitizers in them.Materials and Methods:This was a cross-sectional, hospital-based study in which the staff was screened for features of hand eczema and patch testing was done in the suspected cases of allergic contact dermatitis.Results:Out of 340 employees screened, 46 employees (13.5%) suffered from hand eczema. The most common type was wear and tear dermatitis accounting for 17 (36.9%) cases, followed by discoid eczema, pompholyx, focal palmar peeling, finger-tip eczema, hyperkeratotic eczema, ring eczema, and unspecified types. Patch testing was positive in 15 (32.6%) cases. The most common allergen was paraphenylene diamine, followed by fragrance mix, nitrofurazone, mercaptobenzothiazole, potassium bichromate, black rubber mix, and thiuram mix. A statistically significant association (0.001) was found with an underlying history of atopy.Conclusion:Hand eczema is a commonly encountered dermatological complaint in many hospital employees. Proper counseling, work, up, patch testing, and treatment can mitigate the symptoms in such employees.

Positive Patch Test Reactions to Carba Mix and Thiuram Mix: The North American Contact Dermatitis Group Experience (1994–2016)

BACKGROUND/OBJECTIVE This study characterizes concomitant reactions to carba mix (CM) and thiuram mix (TM) in a large North American population. Because thiurams and dithiocarbamates have structural similarity, concomitant reactions are expected. METHODS The 1994-2016 North American Contact Dermatitis Group data were analyzed. Patients with a final reaction interpreted as allergic to either CM or TM were included. RESULTS A total of 49,758 patients were tested to both CM and TM. A total of 3437 (6.9%) had positive reactions to CM and/or TM including the following groups: CM+ only (n = 1403, 40.8%), TM+ only (n = 1068, 31.0%), or both (n = 966, 28.1%). A total of 47.5% of TM+ patients were positive to CM and 40.8% of CM+ patients were positive to TM. Male sex, occupationally related dermatitis, and hand involvement were significantly more common in individuals positive to CM and/or TM as compared with those who were negative (P < 0.0001). More than 80% of CM+/TM+ reactions were currently relevant. Gloves were the most common source of CM and TM; clothing and footwear were also frequent. CONCLUSIONS Carba mix and TM remain important, clinically relevant allergens. Although significant concomitant reaction frequency was demonstrated, more than half of the patients reacting to either CM or TM would have been missed if both had not been tested, underscoring the importance of testing to both.

Patch Testing of Mercaptobenzothiazole and Mercapto Mix: The North American Contact Dermatitis Group Experience, 1994-2016.

Mercapto compounds are a category of rubber accelerators that may cause allergic contact dermatitis. This study characterizes patch test reactions to mercaptobenzothiazole (MBT) and mercapto mix (MM) in a large North American population. The 1994-2016 North American Contact Dermatitis Group screening series data were analyzed. Patients with allergic reactions to either MBT or MM (mercapto+) were included. The following characteristics were analyzed: strength of reaction, clinical and occupational relevance, coreactivity with other rubber accelerators, and sources of exposure. A total of 49,795 patients were tested to mercapto compounds from 1994 to 2016; 633 (1.3%) had positive reactions to MBT and/or MM. The frequency to both MBT and MM significantly decreased over time (P < 0.0001). Mercapto+ patients were significantly more likely to be male, have occupationally related skin disease, and report involvement of the hands and/or feet (P < 0.0001). They were significantly less likely to have face, scalp/ears/neck, or trunk involvement (P ≤ 0.0001). There was significant coreactivity with carba mix (23.4%) and thiuram mix (32.5%). Mercaptobenzothiazole and MM reactions were frequently clinically (81.7% and 83.5%, respectively) and occupationally relevant (29.8% and 33.4%, respectively). Gloves were the most common source (31.3% and 30.9%, respectively). Patch test positivity to mercapto compounds significantly decreased from 1994 to 2016 but remains clinically and occupationally relevant.

Characteristics and incidence of contact dermatitis among hairdressers in north‐eastern Italy

Hairdressers are at high risk of contact dermatitis (CD) due to skin exposure to numerous irritants and haptens in hair products in combination with frequent wet work. To investigate the characteristics and incidence of CD among hairdressers in north-eastern Italy. A total of 324 hairdressers who had been examined and patch tested in north-eastern Italy from 1996 to 2016 were retrospectively identified, and compared with 9669 matched controls. Sensitization to allergens of the hairdressing series was analysed among hairdressers attending an occupational medicine clinic in Trieste, Italy. Incidence data were calculated from 1999 to 2016. Sensitization to p-phenylenediamine, thiuram mix, and N-isopropyl-N'-phenyl-p-phenylenediamine was significantly associated with hairdressing and with hand/forearms dermatitis. Frequent sensitizers from hairdressing series were ammonium persulfate, toluene-2,5-diamine, and p-aminobenzene. The overall incidence of CD declined from 2003 (31.7 cases/10 000 workers) to 2016 (20.8 cases/10 000 workers). Sensitization to several haptens was significantly associated with hairdressing. The incidence of CD among hairdressers in north-eastern Italy has declined in recent years, but is still high. Preventive efforts are needed to reduce the burden of CD in this professional group.