Prevalence and incidence of hand eczema in healthcare workers: A systematic review and meta-analysis.

Healthcare workers (HCWs) are considered a high-risk group for developing hand eczema (HE), mainly owing to wet work and contact with allergens at work. To meta-analyse the prevalence and incidence of HE in HCWs, as well as mapping the prevalence of atopic dermatitis (AD) and HE severity in HCWs. A systematic review and meta-analysis was performed following the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 guidelines. Published literature from 2000 to 2022 was eligible based on predefined inclusion and exclusion criteria. A total of 18 studies were included. Pooled life-time, 1-year and point prevalence of self-reported HE in HCWs was 33.4% (95% confidence interval [CI]: 28.3-38.6), 27.4% (95% CI: 19.3-36.5) and 13.5% (95% CI: 9.3-18.4), respectively. AD prevalence was 15.4% (95% CI: 11.3-19.9). Overall, the majority of HCWs reported mild HE. One included study assessed HE incidence reporting 34 cases/1000 person years. Most studies scored low-moderate using the New Ottawa Scale and the pooled point prevalence data showed broad CIs. In conclusion, the high prevalence of HE in HCWs underlines the increased risk and need for preventive measures for this professional group. There is, however, a need of further standardized high-quality studies.

Quality of patch testing patient's own material in patients with suspected occupational skin diseases throughout Germany: Interim results of the German Social Accident Insurance (DGUV) research project FB 317b.

BACKGROUND: Due to limited availability of commercial test preparations, patch testing patient's own material (POM) is of great importance to diagnose occupational allergic contact dermatitis. OBJECTIVES: To assess the quality of performance and documentation of patch testing with POM in patients with suspected occupational skin diseases (OSD) in Germany. METHODS: Retrospective-prospective analysis of protocols of patch tests with POM was conducted between 2013 and 2021 in patients with suspected OSD and submitted to statutory accident insurance institutions. Assessments were done by predefined criteria. RESULTS: Three thousand and four patch tests with POM from 460 patients were included. A full description of the POM was provided in 73.3% of all tests. The test concentration, test vehicle and pH value were documented in 74.3%, 70.5% and 42.2% of tests, for which the respective parameters were considered relevant. One hundred and sixty-one positive reactions to POM were documented. In 72%, sufficient patch testing with commercial test substances was conducted to investigate the positive reaction. In 30.4%, consecutive patch testing of all ingredients of the POM was done. CONCLUSIONS: The results not only show considerable shortcomings mainly in documentation but also to some extent performance of patch tests with POM in patients with suspected OSD in Germany.

Assessing the efficacy of a German-inspired intervention on occupational contact dermatitis in Denmark: A randomised controlled trial with 3-month follow-up.

BACKGROUND: Occupational contact dermatitis (OCD) is a prevalent, often chronic disease that poses a risk for job loss and decreased quality of life. In Germany, a multi-step prevention programme emphasising early detection and highly specialised multidisciplinary treatment has been implemented with great success. OBJECTIVES: To examine the effectiveness of a Danish-adapted version of the German prevention effort on OCD severity, quality of life and occupational consequences at 3-month follow-up. METHODS: Randomised, controlled trial. Participants were recruited after the first referral from General Practitioner to Dermatologist with suspected OCD. The intervention group (IG) received a Danish-adapted, multidisciplinary intervention, while the control group (CG) navigated the Danish healthcare system without interference from the study. OCD severity, occupational consequences and quality of life were assessed at 3-month follow-up using self-reported questionnaires. RESULTS: A statistically significant decrease in the severity of eczema was found at 3-month follow-up in the IG compared to the CG. The IG were statistically significantly more likely to have seen a dermatologist at 3-month follow-up. Higher treatment level in the IG was indicated by the results but was not statistically significant. No significant difference was found in quality of life or occupational consequences. CONCLUSIONS: These initial findings suggest that early and specialised treatment of OCD improves OCD prognosis.

Impact of atopic dermatitis on occupational contact dermatitis among young people: A retrospective cohort study.

BACKGROUND: Occupational contact dermatitis (OCD) is a common occupational disease. Atopic dermatitis (AD) is a known risk factor for OCD. OBJECTIVES: To determine the prevalence of previously diagnosed AD among young workers with recognized OCD and assess its impact on OCD prognosis. METHODS: A retrospective cohort study. A questionnaire was sent to 6251 workers with recognized OCD who were under 35 years at notification (response rate: 47%). Of the respondents, 2392 answered a question about previous doctor-diagnosed AD and were included in the study. Eczema severity, occupational consequences and quality of life were examined using statistical analyses comparing workers with and without previously diagnosed AD. RESULTS: The prevalence of previously diagnosed AD was 41.8% (95% CI: 39.8-43.8). Women had a higher AD prevalence, and workers with AD reported OCD at a younger age. Workers with AD reported more frequent and severe eczema symptoms and had a higher risk of OCD negatively affecting job and occupation choices. Health-related quality of life was more adversely affected in workers with AD. CONCLUSIONS: AD significantly impacts severity and has long-term consequences for young people with OCD. Targeted prevention strategies need to be developed.

Diagnostics and Prevention of Occupational Allergy in Hairdressers.

PURPOSE OF REVIEW: This study aims to provide an overview on current knowledge on occupational allergic diseases in hairdressers and up-to-date perspectives of prevention. RECENT FINDINGS: Hand eczema (dermatitis) is common in hairdressers, often caused by contact allergy to one or multiple small molecules (haptens) used, e.g., for dyeing, bleaching, and waving/relaxing or by ancillary substances such as preservatives. Hairdressers, compared to other patch-tested patients, have an up to fivefold increased risk to be found sensitized, e.g., against p-phenylenediamine, ammonium persulfate, and glyceryl thioglycolate. Some of these small molecules may induce respiratory sensitization causing allergic rhinitis and/or asthma, notably persulfate salts. Occupational hazards in hairdressing are well described. This knowledge needs to be put into use for risk reduction, mainly by substitution of allergenic ingredients by less allergenic ones, education, and use of ventilation and suitable single-use gloves.

Effects of impermeable and semipermeable glove materials on resolution of inflammation and epidermal barrier impairment after experimental skin irritation.

BACKGROUND: Semipermeable membranes might be suitable for glove liners or comfort gloves in individuals with irritant contact dermatitis (ICD). OBJECTIVES: To evaluate the effects of different glove materials on inflammation and epidermal barrier impairment after experimental skin irritation. METHODS: Nine test areas on the volar forearms of 24 healthy volunteers were irritated with sodium lauryl sulfate (1%) and afterward covered for 6 days (6 or 8 h/day) with semipermeable Sympatex (SYM), vinyl (OCC), combinations of vinyl with Sympatex (SYM/OCC) or cotton (COT/OCC), or left uncovered (CON). Up to day 10, measurements of transepidermal water loss (TEWL), erythema (a*), skin humidity (SH) and visual scoring (VS) were applied. RESULTS: No significant differences in skin parameters were found between COT/OCC and SYM/OCC as well as between each of the combinations and CON. SYM, COT/OCC and SYM/OCC led to better results for most skin parameters than OCC alone. CONCLUSIONS: Occlusive material has a negative impact on skin barrier recovery and inflammation after skin irritation whereas SYM is not inferior to uncovered areas indicating good tolerability. Altogether, the data suggest that SYM is a useful alternative to COT as material for glove liners and comfort gloves in ICD patients.

Genotoxicity of oxidative hair dye precursors: A systematic review.

This systematic review, conducted according to the PRISMA guidelines, focuses on genotoxicity of oxidative hair dye precursors. The search for original papers published from 2000 to 2021 was performed in Medline, Web of Science, Cochrane registry, Scientific Committee on Consumer Safety of the European Commission and German MAK Commission opinions. Nine publications on genotoxicity of p-phenylenediamine (PPD) and toluene-2,5-diamine (p-toluylenediamine; PTD) were included, reporting results of 17 assays covering main genotoxicity endpoints. PPD and PTD were positive in bacterial mutation in vitro assay, and PPD tested positive also for somatic cell mutations in the Rodent Pig-a assay in vivo. Clastogenicity of PPD and PTD was revealed by in vitro chromosomal aberration assay. The alkaline comet assay in vitro showed DNA damage after PPD exposure, which was not confirmed in vivo, where PTD exhibited positive results. PPD induced micronucleus formation in vitro, and increased micronucleus frequencies in mice erythrocytes following high dose oral exposure in vivo. Based on the results of a limited number of data from the classical genotoxicity assay battery, this systematic review indicates genotoxic potential of hair dye precursors PPD and PTD, which may present an important health concern for consumers and in particular for professional hairdressers.

Systematic review on skin adverse effects of important hazardous hair cosmetic ingredients with a focus on hairdressers.

BACKGROUND: The burden of occupational hand eczema in hairdressers is high, and (partly strong) allergens abound in the hair cosmetic products they use. OBJECTIVES: To systematically review published evidence concerning contact allergy to an indicative list of active ingredients of hair cosmetics, namely, p-phenylenediamine (PPD), toluene-2,5-diamine (PTD), persulfates, mostly ammonium persulfate (APS), glyceryl thioglycolate (GMTG), and ammonium thioglycolate (ATG), concerning the prevalence of sensitization, particularly in terms of a comparison (relative risk; RR) between hairdressers and non-hairdressers. METHODS: Following a PROSPERO-registered and published protocol, eligible literature published from 2000 to February 2021 was identified, yielding 322 publications, and extracted in standardized publication record forms, also considering risk of bias. RESULTS: Based on 141 publications, the contact allergy prevalence to PPD was 4.3% (95% CI: 3.8-4.9%) in consecutively patch tested patients. Other ingredients were mostly tested in an aimed fashion, yielding variable, and partly high contact allergy prevalences. Where possible, the RR was calculated, yielding an average increased sensitization risk in hairdressers of between 5.4 (PPD) and 3.4 (ATG). Additional evidence related to immediate-type hypersensitivity, experimental results, exposures, and information from case reports was qualitatively synthesized. CONCLUSIONS: An excess risk of contact allergy is clearly evident from the pooled published evidence from the last 20 years. This should prompt an improvement in working conditions and product safety.

Bleaching powders, bleaching creams and other hair lightening preparations as sources for (airborne) allergic contact dermatitis and other health effects in hairdressers: Results of an empirical study.

BACKGROUND: Various products are available for lightening hair. There are no data on which applications are actually used in hairdressing, impeding proper estimation of actual exposure and necessary preventive measures. OBJECTIVES: To assess information about availability, usage and formulation of lightening preparations in the German hairdressing trade. METHODS: A market survey was conducted and hairdressers were surveyed by online questionnaires. RESULTS: Of 783 hairdressers clicking the link, 565 hairdressers (91.2% female, mean age of 40.2 ± 11.7 years) from all German states responded (response rate: 72.2%). The questionnaire survey has shown that available hair-lightening preparations in the German hairdressing trade are (multiple selection possible): dust-free (88.5%) and non-dust-free bleaching powders (22.1%), bleaching creams (41.9%), high-lifting hair colour creams (88.8%) and normal hair colour creams (58.4%). Five hundred eighteen (91.7%) hairdressers favour lightening hair with powder. The market survey revealed that bleaching powders and creams contain potassium persulfate, ammonium persulfate and sodium persulfate or combinations of these persulfate salts. CONCLUSIONS: Hairdressers are exposed to various hair-lightening applications containing different chemicals. Preventive measures need to address adverse skin and respiratory effects. Implementation of targeted health education already in early career stages (i.e., apprenticeship) seems advisable and can be maintained by refresher trainings.

Association of hairdressing with cancer and reproductive diseases: A systematic review.

OBJECTIVES: To review recent epidemiological studies investigating carcinogenic or reprotoxic effects among hairdressers who seem to be at greater risk for systemic adverse effects of chemicals released from hair care products than consumers. METHODS: A systematic review according to the PRISMA-P guidelines was performed and included studies published from 2000 to August 2021, in which cancer or adverse reproductive effects were diagnosed in 1995 and onward. Data were synthetized qualitatively due to the small number of studies, heterogeneity of study designs, outcomes, and methods. RESULTS: Four studies investigating cancer frequencies and six studies investigating effects on reproduction among hairdressers were identified. All were of good quality and with low risk of bias. Only one of the four studies found an increased risk of cancer reporting nine times higher odds for bladder cancer in hairdressers than the population-based controls. Three other studies investigating bladder and lung cancer, and non-Hodgins lymphoma did not find an increased risk in hairdressers. Regarding reprotoxic effects, numerous outcomes were investigated including menstrual disorders, congenital malformations, fetal loss, small-for-gestational age newborns, preterm delivery, and infertility. Increased risk was found for ventricular septal defect in newborns of fathers working as hairdressers. Furthermore, several indices of poor neonatal or maternal health were significantly associated with mothers working as hairdresser. CONCLUSIONS: Despite the scarce evidence that hairdressers are at increased risk of carcinogenic or reprotoxic effects related to their trade, such health risks cannot be ruled out. Therefore, preventive efforts to diminish occupational exposures to hairdressing chemicals should be targeted.

Occupational Exposure of Hairdressers to Airborne Hazardous Chemicals: A Scoping Review.

INTRODUCTION: Exposure to hazardous chemicals released during hairdressing activities from hair care products puts hairdressers at risk of adverse health effects. Safety assessments of hair products are mainly focused on consumers, but exposure for professional hairdressers might be substantially higher. OBJECTIVE: To identify and assess available research data on inhalation exposures of professional hairdressers. METHODS: A systematic search of studies between 1 January 2000 and 30 April 2021 was performed in Medline, Embase, Web of Science and in Cochrane registry, toxicological dossiers of the Scientific Committee on Consumer Safety (SCCS) of the European Commission as well as the German MAK Commission. Studies reporting quantitative data on airborne concentrations of chemicals in the hairdresser's workplace were considered. The outcome was an airborne concentration of chemicals in the working environment, which was compared, when possible, with current occupational exposure limits (OEL) or guidance levels. RESULTS: In total, 23 studies performed in 14 countries were included. The average number of hairdressing salons per study was 22 (range 1-62). Chemicals most frequently measured were formaldehyde (n = 8), ammonia (n = 5), total volatile organic compounds (TVOC) (n = 5), and toluene (n = 4). More than fifty other chemicals were measured in one to three studies, including various aromatic and aliphatic organic solvents, hydrogen peroxide, persulfate, and particulate matter. Most studies reported environmental air concentrations, while personal exposure was measured only in seven studies. The measured air concentrations of formaldehyde, ammonia, and TVOC exceeded OEL or guidance values in some studies. There was large variability in measuring conditions and reported air concentrations differed strongly within and between studies. CONCLUSION: Hairdressers are exposed to a wide spectrum of hazardous chemicals, often simultaneously. Airborne concentrations of pollutants depend on salon characteristics such as ventilation and the number of customers but also on used products that are often country- or client-specific. For exposure to formaldehyde, ammonia, and TVOC exceeding OELs or guidance values for indoor air was observed. Therefore, occupational exposure should be taken into account by safety regulations for hair care products.

Respiratory toxicity of persulphate salts and their adverse effects on airways in hairdressers: a systematic review.

OBJECTIVE: To review the literature on respiratory effects of persulfate salts (PS) or hair bleaches in hairdressers and animal models exploring mechanisms behind PS-induced asthma. METHODS: A systematic review according to the PRISMA guidelines was performed. Studies published from 2000 to July 2021 that fulfilled predefined eligibility criteria were retrieved. Data were not quantitatively synthesized due to the heterogeneity of study designs, outcomes and methods. RESULTS: Forty-two articles were included. PS are indicated as the main cause of occupational rhinitis and asthma in hairdressers, and one of the leading causes of occupational asthma in some European countries. Bleaching products are indicated as the most important factor for development of respiratory symptoms, lung function decline, and leaving the hairdressing profession. Risk estimates from a good quality prospective study showed up to 3.9 times higher risk for wheezing and breathlessness in hairdressers aged ≥ 40 years than in matched controls, and 20 times higher risk in hairdressers to develop respiratory symptoms from exposure to bleaching powder than controls. Pathophysiological mechanisms of the respiratory response to PS are not yet fully elucidated, but may include non-specific and specific immune responses. CONCLUSIONS: Hairdressing is associated with a wide spectrum of respiratory adverse effects, of which bleaching products were indicated as the most hazardous. Preventive measures for reducing inhalatory exposure to PS in hair salons should be re-evaluated, including adopting occupational exposure limits at EU level, and encouraging use of safer bleach formulations. PROSPERO REGISTRATION NUMBER: CRD42021238118.

Nickel and cobalt release from beauty tools: A field study in the German cosmetics trade.

BACKGROUND: Relevant nickel and cobalt release from hairdressing tools has recently been evidenced. Comparable data are not available for tools used in beauty salons. OBJECTIVES: Screening of beauty tools for nickel and cobalt release. METHODS/MATERIALS: Three hundred eight beauty tools were tested in seven beauty salons located in two North-German states. A nickel spot test and a cobalt spot test were used to test the tools for nickel release and cobalt release, respectively. RESULTS: One hundred forty-three of 308 beauty tools overall (46.4%; 95% confidence interval [CI]: 40.8%-52.2%) released nickel and 18 of 308 beauty tools overall (5.8%; 95%CI: 3.5%-9.1%) released cobalt. Nickel release was found in 22 of 99 metal tools (22.2%; 95%CI: 14.5%-31.7%) and 121 of 209 tools with metallic parts (57.9%; 95%CI: 50.9%-64.7%); cobalt release was detected in 3 of 99 metal tools (3.0%; 95%CI: 0.63%-8.6%) and 15 of 209 tools with metallic parts (7.2%; 95%CI: 4.1%-11.6%). CONCLUSIONS: Nickel and cobalt are emitted at allergologically relevant levels by a wide range of beauty tools (i.e., metal tools and tools with metallic parts) utilized in the German cosmetics trade. Beauty tools should thus be considered occupational sources of nickel and cobalt exposure.

European patch test results with audit allergens as candidates for inclusion in the European Baseline Series, 2019/20: Joint results of the ESSCAA and the EBSB working groups of the ESCD, and the GEIDACC.

BACKGROUND: In 2019, a number of allergens (haptens), henceforth, "the audit allergens," were considered as potential additions to the European Baseline Series (EBS), namely, sodium metabisulfite, 2-bromo-2-nitropropane-1,3-diol, diazolidinyl urea, imidazolidinyl urea, Compositae mix II (2.5% or 5% pet), linalool hydroperoxides (lin-OOH), limonene hydroperoxides (lim-OOH), benzisothiazolinone (BIT), octylisothiazolinone (OIT), decyl glucoside, and lauryl glucoside; Evernia furfuracea (tree moss), was additionally tested by some departments as well. OBJECTIVES: To collect further data on patch test reactivity and clinical relevance of the audit allergens in consecutive patients across Europe. METHODS: Patch test data covering the audit allergens in 2019 and 2020 were collected by those departments of the European Surveillance System on Contact Allergies testing these, as well as further collaborators from the EBS working group of the European Society of Contact Dermatitis (ESCD), and the Spanish Grupo Español de Investigación en Dermatitis de Contacto y Alergia Cutánea. As patch test outcome, reactions between day (D) 3 and D5 were considered. RESULTS: Altogether n = 12 403 patients were tested with any of the audit allergen. Positive reactions were most common to lin-OOH 1% pet. (8.74% [95%CI: 8.14-9.37%]), followed by lin-OOH 0.5% pet., and lim-OOH 0.3% pet (5.41% [95% CI: 4.95-5.89%]). Beyond these terpene hydroperoxides, BIT 0.1% pet. was the second most common allergen with 4.72% (95% CI: 4.2-5.28%), followed by sodium metabisulfite 1% pet. (3.75% [95%CI: 3.32-4.23%]) and Compositae mix 5% pet. (2.31% [95% CI: 1.84-2.87%]). For some allergens, clinical relevance was frequently difficult to ascertain. CONCLUSIONS: Despite many positive patch test reactions, it remains controversial whether lin- and lim-OOH should be tested routinely, while at least the two preservatives BIT and sodium metabisulfite appear suitable. The present results are a basis for further discussion and ultimately decision on their implementation into routine testing among the ESCD members.

Differences between hairdressers and consumers in skin exposure to hair cosmetic products: A review.

Hairdressers are at high risk of developing occupational hand eczema. Opinions on the health and safety concerns of nonfood consumer products, such as cosmetics and their ingredients, consider the exposure of a "common consumer," which may not account for occupational exposure of hairdressers. As a result, there is a parlous scenario in which serious safety concerns about occupational exposures are present. The purpose of this review is to compare the frequency of exposure to various types of hair cosmetic products among hairdressers and consumers. Database searches for this review yielded a total of 229 articles; 7 publications were ultimately included. The analysis showed that-dependent on the task-hairdressers were exposed 4 to 78 times more than consumers to a wide spectrum of hair cosmetic products used in their daily working life, ranging from shampoos, conditioners, oxidative and nonoxidative hair colors, to bleaching agents. The highest frequency was found for coloring hair with oxidative hair color. Consumer use frequency does not appear to be appropriate for representing hairdresser exposure. The current standards do not effectively address the occupational risks associated with hairdressers' use of cosmetics. The findings of this study should cause current risk-assessment procedures to be reconsidered.

Allergic contact dermatitis caused by 2-hydroxyethyl methacrylate and ethyl cyanoacrylate contained in cosmetic glues among hairdressers and beauticians who perform nail treatments and eyelash extension as well as hair extension applications: A systematic review.

Current cosmetic regulations primarily focus on protecting consumers, not the professional user who is subjected to a partly different, and certainly more intense exposure to hazardous substances. Against this background, this systematic review aims to compile and appraise evidence regarding skin toxicity of 2-hydroxyethyl methacrylate (HEMA; CAS no. 212-782-2) and ethyl cyanoacrylate (ECA; CAS no. 7085-85-0) contained in cosmetic glues used among hairdressers and beauticians who perform nail treatments and eyelash extension as well as hair extension applications. This systematic review followed the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) 2020 recommendations for reporting systematic reviews and meta-analysis. In total, six publications from six countries were eligible for this systematic review. A meta-analysis revealed that hairdressers and beauticians have a ninefold increased risk of developing contact allergy to HEMA compared with controls who are not hairdressers and beauticians. Results for ECA are lacking. The results of this systematic review clearly show that-regarding contact allergy to acrylates-it is not appropriate to apply risk assessment for consumers to hairdressers and beauticians who occupationally handle cosmetic glues. The regulations in existence do not adequately address occupational risks for hairdressers and beauticians connected with the use of acrylate-containing cosmetic substances and need reconsideration.

Occupational contact dermatitis among young people in Denmark - A survey of causes and long-term consequences.

BACKGROUND: Studies on the causes and consequences of occupational contact dermatitis (OCD) among young workers are non-existent. OBJECTIVES: Determine causes and consequences of OCD among workers younger than 35 years of age. METHODS: A questionnaire was sent to 6251 workers younger than 35 years at notification with recognized OCD (response rate 47%). RESULTS: The most prevalent occupations were health care workers, kitchen workers, nursery teachers, and hairdressers and beauticians. Seventy-six percent still had eczema, and 77% of these had eczema half to all the time over the last 3 months, with 61% evaluating their eczema as moderate to very severe. Fifty-three percent had changed their occupation since notification, and 42.5% had lost their job because of OCD. Allergic OCD increased the odds ratio (OR) for facial or foot eczema, job loss, change in work tasks, difficulties finding work, decrease in income, and sick leave. Age at notification of 25 years of age or younger increased the risk of job loss and feeling restricted in choice of job. Workers in the food industry had a higher OR for job loss, whereas hairdressers and beauticians had a higher risk of job loss and a decrease in income. CONCLUSIONS: The severe, long-term consequences of OCD notification signify the need for further preventive strategies among young workers.

Prevalence and incidence of hand eczema in hairdressers-A systematic review and meta-analysis of the published literature from 2000-2021.

BACKGROUND: Hairdressers are commonly affected by hand eczema (HE) due to skin hazardous exposure such as irritants and allergens in the work environment. OBJECTIVE: To give an overview of the current prevalence, incidence, and severity, as well as the pattern of debut and the contribution of atopic dermatitis on HE in hairdressers. METHODS: A systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines was performed. Studies published from 2000 to April 2021 that fulfilled predefined eligibility criteria were retrieved. RESULTS: A pooled lifetime prevalence of 38.2% (95% confidence interval [CI] 32.6-43.8), a pooled 1-year prevalence of 20.3% (95% CI 18.0-22.6), and a pooled point prevalence of 7.7% (95% CI 5.8-9.6) of HE was observed in hairdressers. The lifetime prevalence in fully trained hairdressers and hairdressing apprentices was almost identical. The pooled incidence rate of HE was 51.8 cases/1000 person-years (95% CI 42.6-61.0) and the pooled prevalence of atopic dermatitis was 18.1% (95% CI 13.6-22.5). CONCLUSION: HE is common in hairdressers and most hairdressers have debut during apprenticeship. The prevalence of atopic dermatitis in hairdressers is comparable with estimates in the general population, indicating that occupational exposures are the main factor in the increased prevalence of HE in hairdressers. This warrants a strategic and collective effort to prevent HE in hairdressers.