Glove use among hairdressers: difficulties in the correct use of gloves among hairdressers and the effect of education.

BACKGROUND: Hand eczema is frequent among Danish hairdressers, and they are advised to use gloves as protection. However, studies indicate that a significant proportion use gloves inappropriately. OBJECTIVES: To determine whether hairdressers and apprentices use protective gloves in the correct way, and to determine whether a demonstration of correct use could cause an improvement. METHODS: Forty-three hairdressers and apprentices were asked to perform a hair wash while wearing gloves. The shampoo used was contaminated with an ultraviolet (UV) trace material. Two rounds of hair washing were carried out by each person, interrupted by a demonstration of how to use gloves correctly. Photographs were taken to compare UV contamination before and after the demonstration. RESULTS: All of the participants (100%) had their hands contaminated during the first round; the area ranged between 0.02 and 101.37 cm(2) (median 3.62 cm(2)). In the second round, 55.8% were contaminated (range 0.00-3.08 cm(2) ; median 0.01 cm(2)). The reduction in contaminated skin areas was statistically significant (p < 0.001), proving an effect of the glove demonstration. There were no significant differences between hairdressers and apprentices. CONCLUSIONS: Hairdressers and apprentices lack knowledge on how to handle gloves correctly. A short demonstration of correct glove use made a significant difference in the skin protection provided by gloves.

Occupational skin diseases in hairdressing apprentices - has anything changed?

BACKGROUND: Hairdressers are at risk for occupational skin diseases. Since 2008, an educational programme has been conducted in Danish hairdressing schools to prevent occupational skin diseases. Its effect is unknown. OBJECTIVE: To examine the current frequency of self-reported hand eczema and contact urticaria in Danish hairdressing apprentices as compared with controls, and to determine the occurrence of hand eczema and contact urticaria in hairdressing apprentices with different durations of exposure to the trade. METHODS: This was a cross-sectional, web-based questionnaire study conducted among 504 hairdressing apprentices and a control group of 1400 adolescents from the general population. RESULTS: Hand eczema was significantly more prevalent in the hairdressing apprentices than in controls (34.5% versus 18.8%, p < 0.001). The incidence rate of hand eczema among hairdressing apprentices was 98 cases/1000 person-years. Contact urticaria was also more prevalent in the hairdressing apprentices (7.3% versus 4.2%, p = 0.006). Both diseases increased with increasing duration of exposure to the trade. CONCLUSION: Despite educational efforts to prevent occupational skin diseases in the hairdressing schools, Danish apprentices are still at increased risk for hand eczema and contact urticaria. Both diseases develop after only a few years of work in hairdressing. Further preventive strategies are warranted.

Occupational contact dermatitis in hairdressers: an analysis of patch test data from the Danish contact dermatitis group, 2002-2011.

BACKGROUND: Occupational contact dermatitis among hairdressers is frequent, owing to daily exposure to irritants and allergens. OBJECTIVES: To identify sensitization to the most common allergens associated with the occupation of hairdressing. METHODS: Patch test results of 399 hairdressers and 1995 matched controls with contact dermatitis, registered by the Danish Contact Dermatitis Group between January 2002 and December 2011, were analysed. All patients were patch tested with the European baseline series, and hairdressers were additionally tested with the hairdressing series. RESULTS: Occupational contact dermatitis (p < 0.001) and hand eczema (p < 0.001) were observed significantly more often among hairdressers than among controls. Atopic dermatitis was less commonly observed among hairdressers (21.3%) than among controls (29.4%) (p < 0.01). Allergens from the European baseline series with a statistically significant association with the occupation of hairdressing were p-phenylenediamine, thiuram mix, and benzocaine. Frequent sensitizers from the hairdressing series were ammonium persulfate, toluene-2,5-diamine, 3-aminophenol, and 4-aminophenol. Cysteamine hydrochloride and chloroacetamide emerged as new sensitizers. CONCLUSIONS: These results indicate a healthy worker effect among hairdressers diagnosed with eczema. Ammonium persulfate and p-phenylenediamine remain frequent sensitizers in hairdressers with contact dermatitis. Cysteamine hydrochloride and chloroacetamide should be included in future surveillance studies.

Asthma and respiratory symptoms among hairdressers in Denmark: results from a register based questionnaire study.

BACKGROUND: Hairdressers are at risk of developing occupational respiratory disorders due to persulfates and other hairdressing chemicals. METHODS: A register based questionnaire study comprising 7,840 graduates from hairdressing vocational schools was conducted. The postal questionnaire concerned self-reported asthma, airway symptoms, occupation, smoking, and atopic dermatitis. RESULTS: A response rate of 67.9% was obtained. The hairdressers reported asthma (11.2%), cough (25.3%), nasal congestion (24.0%), and rhinitis (18.2%). Less than 1/3 of all hairdressers with suspected occupational asthma reported their asthma as an occupational disease to the authorities. In total, 27.3% were daily smokers; the smoking pattern was similar between hairdressers with and without asthma. Local exhaust ventilation was only used consistently by 63.8% for permanent waving and hair coloring procedures. CONCLUSIONS: Asthma and especially respiratory symptoms were commonly reported by hairdressers, but rarely reported as an occupational disease. Local exhaust ventilation was inconsistently used. Our results underline the need for improved measures to ascertain and prevent occupational asthma in hairdressers.

Contact allergy to common ingredients in hair dyes.

BACKGROUND: p-Phenylenediamine (PPD) is the primary patch test screening agent for hair dye contact allergy, and approximately 100 different hair dye chemicals are allowed. OBJECTIVES: To examine whether PPD is an optimal screening agent for diagnosing hair dye allergy or whether other clinically important sensitizers exist. METHODS: Two thousand nine hundred and thirty-nine consecutive patients in 12 dermatology clinics were patch tested with five hair dyes available from patch test suppliers. Furthermore, 22 frequently used hair dye ingredients not available from patch test suppliers were tested in subgroups of ~500 patients each. RESULTS: A positive reaction to PPD was found in 4.5% of patients, and 2.8% reacted to toluene-2,5-diamine (PTD), 1.8% to p-aminophenol, 1% to m-aminophenol, and 0.1% to resorcinol; all together, 5.3% (n = 156). Dying hair was the most frequently reported cause of the allergy (55.4%); so-called 'temporary henna' tattoos were the cause in 8.5% of the cases. p-Methylaminophenol gave a reaction in 20 patients (2.2%), 3 of them with clinical relevance, and no co-reaction with the above five well-known hair dyes. CONCLUSIONS: Hair dyes are the prime cause of PPD allergy. PPD identifies the majority of positive reactions to PTD, p-aminophenol and m-aminophenol, but not all, which justifies additional testing with hair dye ingredients from the used product.

Prevention of hand eczema among Danish hairdressing apprentices: an intervention study.

OBJECTIVES: To investigate whether an evidence-based intervention could reduce the incidence of hand eczema in a cohort of Danish hairdressing apprentices during their training, as hairdressing apprentices are known to have a high risk of developing hand eczema. METHODS: This study was a clinically controlled, prospective intervention study. Within 2 weeks of starting their training, 502 hairdressing apprentices were enrolled in the study on occupational hand eczema. Approximately half of the apprentices were assigned to an intervention group and received an evidence-based training program developed for this study and delivered by teachers specially trained in the prevention of hand eczema; the other half received normal training and served as a control group. All apprentices completed self-administered questionnaires including questions regarding hand eczema, use of gloves and degree of wet work, and were all clinically examined for hand eczema three times during the 18-month study period. The three examinations were scheduled as school visits and consisted of a baseline examination and two follow-up examinations approximately 8 and 18 months later. RESULTS: More apprentices from the intervention group used gloves during wet work procedures and significantly fewer developed hand eczema compared with apprentices from the control group (p=0.04). A logistic regression model showed that atopic dermatitis had a significant influence on the development of hand eczema in the cohort irrespective of the intervention. CONCLUSIONS: We were able to increase the use of gloves and reduce the incidence of hand eczema in hairdressing apprentices by implementing a training program in hairdressing schools.

Do hairdressers in Denmark have their hand eczema reported as an occupational disease? Results from a register-based questionnaire study.

BACKGROUND: Occupational hand eczema is common in hairdressers, owing to wet work and chemicals. OBJECTIVES: To estimate whether hairdressers in Denmark have their hand eczema reported as an occupational disease and to clarify the reasons for not reporting. METHODS: A register-based study was performed, comprising trained hairdressers (n = 7840), using a self-administered postal questionnaire including questions on hand eczema and it being reported as an occupational disease. A response rate of 67.9% (n = 5324) was obtained. RESULTS: Overall, 2186 respondents ever had hand eczema; 71.3% were apprentices at the time of hand eczema onset. The majority (61.9%) had had hand eczema several times and 21.3% (almost) all of the time, but only 20.7% had reported their hand eczema as being occupational to the National Board of Industrial Injuries (Denmark). A positive association between severity of hand eczema and filing a report was found (odds ratio 19.2; 95% confidence interval 8.18-45.06). The main reasons for not reporting were 'I thought it would eventually get better' (40.4%) and 'My doctor didn't tell me it was possible to report it' (26.6%). CONCLUSIONS: Hand eczema is considerably under-reported as an occupational disease; the perception of hand eczema among hairdressers and the lack of reporting from doctors are the main reasons for this.

A quantification of occupational skin exposures and the use of protective gloves among hairdressers in Denmark.

BACKGROUND: Occupational hand eczema is common in hairdressers, owing to excessive exposure to wet work and hairdressing chemicals. OBJECTIVES: To quantify occupational skin exposure and the use of protective gloves among hairdressers in Denmark. METHODS: A register-based study was conducted comprising all graduates from hairdressing vocational schools from 1985 to 2007 (n = 7840). The participants received a self-administered postal questionnaire in May 2009, including questions on hairdressing tasks performed in the past week at work and the extent of glove use. A response rate of 67.9% (n = 5324) was obtained. RESULTS: Of the respondents, 55.7% still worked as hairdressers, and they formed the basis of this study. Daily wet work was excessive; 86.6% had wet hands for ≥2 hr, and 54% for ≥ 4 hr. Glove use was fairly frequent for full head hair colouring and bleaching procedures (93-97.7%), but less frequent for highlighting/lowlighting procedures (49.7-60.5%) and permanent waving (28.3%). Gloves were rarely worn during hair washing (10%), although this was more frequently the case after hair colouring procedures (48.9%). CONCLUSIONS: Occupational skin exposure was excessive among hairdressers; the extent of wet work and chemical treatments was high, and glove use was inconsistent, especially for certain hair colouring procedures and wet work tasks.

Self-testing for contact sensitization to hair dyes--scientific considerations and clinical concerns of an industry-led screening programme.

The cosmetic industry producing hair dyes has, for many years, recommended that their consumers perform 'a hair dye allergy self-test' or similar prior to hair dyeing, to identify individuals who are likely to react upon subsequent hair dyeing. This review offers important information on the requirements for correct validation of screening tests, and concludes that, in its present form, the hair dye self-test has severe limitations: (i) it is not a screening test but a diagnostic test; (ii) it has not been validated according to basic criteria defined by scientists; (iii) it has been evaluated in the wrong population group; (iv) skin reactions have been read by dermatologists and not by the targeted group (consumers and hairdressers); (v) hair dyes contain strong and extreme sensitizers that are left on the skin in high concentrations, potentially resulting in active sensitization; and (vi) recommendations and instructions on how to perform the hair dye self-test vary greatly even among products from the same company, again suggesting that the basis for safe use of the test has not been determined. If the use of a hair dye self-test to predict contact sensitization becomes widespread, there is severe risk that a tool has been marketed that may cause morbidity in European consumers.

Hand eczema in hairdressers: a Danish register-based study of the prevalence of hand eczema and its career consequences.

BACKGROUND: Occupational hand eczema is common in hairdressers, owing to wet work and hairdressing chemicals. OBJECTIVES: To estimate the prevalence of hand eczema and its career consequences among hairdressers in Denmark. METHODS: A register-based study was conducted, comprising all graduates from hairdressing vocational schools from 1985 to 2007 (n = 7840). The participants received a self-administered postal questionnaire including questions on hand eczema, atopic dermatitis, and career change. A response rate of 67.9% (n = 5324) was obtained. RESULTS: Of the respondents, 44.3% no longer worked as hairdressers and had worked for an average of 8.4 years in the profession before leaving it. Hand eczema was more common among ex-hairdressers (48.4%) than among current hairdressers (37.6%) (p < 0.0001), and significantly more ex-hairdressers (26.8%) than current hairdressers (15.7%) had chronic hand eczema (p < 0.0001). Of the respondents with hand eczema, 75% were aged 15-24 years at onset, and 45.5% gave hand eczema as a reason for career change. In this group, logistic regression analysis showed that chronic hand eczema contributed the most to the decision to change career (odds ratio 50.12; 95% confidence interval 18.3-137). CONCLUSIONS: Hairdressers work an average of 8.4 years in the profession before leaving it, and hand eczema contributes significantly to this career change.

Healthy worker effect in hairdressing apprentices.

BACKGROUND: Hairdressers and hairdressing apprentices have a high incidence of occupational hand eczema, owing to excessive wet work and exposure to chemical substances. Hairdressing apprentices, in particular, seem to be at high risk of developing hand eczema. Previous hand eczema and atopic dermatitis are known risk factors for the development of hand eczema in wet work occupations. OBJECTIVES: To estimate the prevalence of hand eczema, eczema on wrists or forearms and atopic dermatitis in a cohort of hairdressing apprentices at the start of their education, and subsequently evaluate any potential healthy worker effect. METHODS: During the first 2 weeks of training, 382 hairdressing apprentices were enrolled in this study. All apprentices completed a self-administered questionnaire, including previously validated questions regarding, for example, previous and present hand eczema, eczema on the wrists or forearms, and atopic dermatitis. For comparison, the questionnaire was sent to a control group matched for age, gender and city code from the general population (n = 1870). RESULTS: Response rates were 99.7% for the hairdressing apprentices (mean age 17.5 years, range 15-39 years, 96.3% females) and 68.3% for the control group (mean age 17.4 years, range 15-39 years, 96.8% females). Previous or present hand eczema were reported by 8.0% of hairdressing apprentices and by 12.5% of the matched control group (p = 0.009), and eczema on the wrists or forearms was reported by 5.3% of the apprentices and by 11.9% of the controls (p < 0.001). We classified 21.4% of the hairdressing apprentices as having atopic dermatitis versus 29.8% of the matched control group (p = 0.001). CONCLUSIONS: These results indicate a healthy worker effect, as there was a lower reported incidence of hand eczema and eczema on wrists or forearms, and there were fewer cases classified as having atopic dermatitis, among hairdressing apprentices than in a matched control group from the general population.

Exposures and reactions to allergens among hairdressing apprentices and matched controls.

BACKGROUND: Early and extensive exposures to chemical substances such as are found in hair dyes, perfumes and nickel are known risk factors for allergic reactions. Hairdressing apprentices belong to a high-risk group, as they are exposed both occupationally and personally. OBJECTIVES: To estimate the degree of exposure and adverse skin reactions to chemical substances in a cohort of hairdressing apprentices, at the start of their education, as compared with a matched sample from the general population. MATERIALS: During their first 2 weeks of training, 382 hairdressing apprentices were enrolled in this study. All apprentices completed a self-administered questionnaire that included questions regarding, for example, exposures and skin reactions to hair dye, perfumed products, and piercings. For comparison, the questionnaire was sent to a control group from the general population, matched on age, sex, and postal code (n = 1870). RESULTS: Within the previous year, 95.2% of hairdressing apprentices and 66.9% of the control group had dyed their hair (p < 0.001); the apprentices dyed their hair, on average, 6.6 times per year, as compared with 3.7 times per year in the control group (p < 0.001). The mean age of the first hair dying among the apprentices was 12.1 years, as compared with 13.3 years for the matched control group (p < 0.001). The hairdressing apprentices reported more eczematous reactions to hair dye (p = 0.002) than the controls. Semi-permanent so-called 'black henna tattoos' had been carried out in 48.1% of the apprentices, as compared with 31.0% of the controls (p < 0.001). CONCLUSIONS: Both hairdressing apprentices and the matched control group of young people from the general population were highly exposed to potent allergens. The hairdressing apprentices were even more exposed to products containing hair dye substances and piercings, and reported more adverse reactions to hair dye products than their matched controls from the general population.

Validation of self-reporting of hand eczema among Danish hairdressing apprentices.

BACKGROUND: Hairdressing apprentices have a high incidence of hand eczema. Most studies use self-reported hand eczema as a cost-effective method to estimate the prevalence of hand eczema. No validation studies on self-reported hand eczema among hairdressing apprentices exist. OBJECTIVES: To evaluate the validity of self-reporting of hand eczema among Danish hairdressing apprentices. METHODS: During their first 2 weeks of training, 502 hairdressing apprentices were enrolled in this study. All apprentices completed a self-administered questionnaire including questions regarding, for example, current hand eczema, and they were all clinically examined for hand eczema three times during the first part of their education by use of the Hand Eczema Severity Index. The validity of self-reporting of hand eczema was measured with the clinical examination as the gold standard. RESULTS: The sensitivity of self-reporting of hand eczema was 70.3%, and the specificity was 99.8%. The positive predictive value was 96.3%, and the negative predictive value was 98.5%. CONCLUSIONS: We found good agreement between self-reporting of hand eczema and clinical examination. There was good sensitivity and high specificity. Self-reporting of hand eczema among hairdressing apprentices is considered to be a valid method for estimating the prevalence of hand eczema, although it might underestimate the true prevalence.

Personal use of hair dyes and temporary black tattoos in Copenhagen hairdressers.

BACKGROUND: Hairdressers are occupationally and personally exposed to hair dye substances and adverse reactions from the skin are well known. Currently, little is known about personal exposure to hair dye ingredients and temporary black tattoos. OBJECTIVES: To investigate hairdressers' professional and personal risk exposures and to compare the frequency of temporary tattoos among hairdressers and subjects from the general population. METHODS: A questionnaire was sent to 1679 Copenhagen hairdressers and 1063 (63.3%) responded; 3471 subjects from the general population in Copenhagen were asked about temporary black tattoos. RESULTS: Of the female hairdressers, 38.3% had coloured hair within the previous week. Adverse skin reactions to own hair dye were reported in 29.5%. In the hairdresser population, no significant association was observed between self-reported adverse skin reactions to hair dye and having had a temporary black tattoo when adjusted for sex, age, and atopy. A total of 19.0% of hairdressers (43.5% of apprentices) and 6.3% of participants from the general population had ever had a temporary black tattoo performed at one point. There were no differences in frequency of eczema after temporary tattooing between hairdressers and subjects in the general population. Almost all hairdressers (99.2%) used gloves for hair colouring, 51% for high/low lighting, 39.6% for perming and 21.1% used gloves for shampooing. CONCLUSIONS: In conclusion, skin reactions to hair colour are frequent among Copenhagen hairdressers. Temporary black tattoos were more frequent among hairdressers than in a sample of the general population and increased with decreasing age.

Nickel allergy in patch-tested female hairdressers and assessment of nickel release from hairdressers' scissors and crochet hooks.

BACKGROUND: Hand eczema as well as nickel contact allergy is prevalent among hairdressers. Recently, two female hairdressers were diagnosed with nickel contact allergy-related hand eczema following prolonged skin contact with scissors and crochet hooks used during work. OBJECTIVES: To determine the proportion of hairdressers' scissors and crochet hooks that released an excessive amount of nickel and to determine the prevalence of nickel allergy among patch-tested female hairdressers. MATERIALS: Random hairdressers' stores in Copenhagen were visited. The dimethylglyoxime (DMG) test was used to assess excessive nickel release. The prevalence of nickel allergy among female hairdressers from the database at Gentofte Hospital was compared with the prevalence of nickel allergy among other consecutively patch-tested dermatitis patients. RESULTS: DMG testing showed that 1 (0.5%; 95% CI = 0 - 2.0) of 200 pairs of scissors and 7 (53.8%; 95% CI = 26.0 - 82.0) of 13 crochet hooks released an excessive amount of nickel. The prevalence of nickel allergy was higher among middle-aged and older female hairdressers than among young female hairdressers. CONCLUSIONS: The prevalence of nickel allergy was lower among young hairdressers in comparison to older hairdressers. This may possibly be a result of the European Union (EU) Nickel Directive or a consequence of a decreased use of nickel-releasing work tools in salons. When nickel allergic hairdressers present with hand eczema, their work tools should be investigated for nickel release.

High occurrence of rhinitis symptoms in hairdressing apprentices.

BACKGROUND: Little is known about the occurrence of respiratory symptoms among hairdressing apprentices during their training. Therefore, in this study, we examined whether hairdressing apprentices are at increased risk of rhinitis and asthma symptoms when compared with other young adults from the general population. METHODS: A questionnaire was completed by 504 hairdressing apprentices and 1400 control participants from the general population with a similar age, gender, and geographic distribution. RESULTS: The 1-year prevalence of rhinitis symptoms was higher in hairdressing apprentices than in controls (58.1% vs 46.6%; odds ratio, 1.59; 95% confidence interval, 1.30-1.98), and the prevalence was higher among hairdressing apprentices in the last years of training compared with apprentices in the first year of training (62.4% vs 41.8%, p = 0.003). Current smoking was more common in hairdressing apprentices (28.4% vs 17.2%, p < 0.001). Asthma symptoms were equally common in the 2 groups; however, hairdressing apprentices had a later age of onset of wheezing than did the controls (18 years vs 14 years, p < 0.00001) and a decreased risk of wheezing (odds ratio, 0.72; 95% confidence interval, 0.54 to 0.95) after adjusting for smoking, education level, and degree of rurality. Bleaching products were the most frequently reported cause of rhinitis and asthma symptoms in hairdressing apprentices. CONCLUSIONS: Hairdressing apprentices seem to have an increased risk of occupational rhinitis, and bleaching products are the main cause of respiratory symptoms. In addition, our findings suggest that a healthy worker effect exists in relation to asthma among hairdressing apprentices.

Chemical intolerance among hairdressers in Denmark.

OBJECTIVES: To investigate the prevalence and the severity of fragrance-related symptoms among hairdressers in Denmark compared with the Danish general population. Further, to characterize former hairdressers who are severely chemically intolerant to fragranced products in relation to sex, age and health- and work-related reasons for leaving the hairdressing profession. METHODS: The study population consisted of all hairdressers who graduated from the public vocational schools in Denmark during 1985 and 2007 (n = 7840) and a random sample of individuals from the Danish general population (n = 6000). Both populations received a postal questionnaire on symptoms from inhalation of fragranced products and the resultant behavioural consequences. All former hairdressers also answered additional questions on health- and work-related reasons for leaving the profession. RESULTS: No differences were found in the prevalence (OR = 1.0, CI = 0.89-1.14) or the severity (OR = 1.1, CI = 0.80-1.51) of symptoms from inhalation of fragranced products in hairdressers compared with the general population. Among hairdressers, however, experience of fragrance-related symptoms (OR = 1.2, CI = 1.01-1.31) and adjustments of social (OR = 1.8, CI = 1.12-2.80) and occupational conditions (OR = 2.8, CI = 1.84-4.25) were reported significantly more often by former hairdressers than current hairdressers. CONCLUSIONS: The prevalence and the severity of fragrance-related symptoms were similar in hairdressers and the general population. Former hairdressers were more affected by fragranced products than current hairdressers were. Although fragrance-related symptoms did not seem to be more frequent among hairdressers, the hairdressing profession might pose a problem for those who are chemically intolerant.

Occupational eczema and asthma in a hairdresser caused by hair-bleaching products.

Occupational allergic contact eczema and asthma caused by bleaching agents is seen in hairdressers. Bleaching agents contain persulfate salts, which are known to induce immediate reactions such as rhinitis, asthma, contact urticaria, and anaphylaxis. The immunologic mechanism is not, however, fully understood. The specific inhalation challenge test is considered to be the gold standard for diagnosing occupational asthma and rhinitis. However, this test is not always accessible. Therefore, the diagnosis of occupational allergic asthma caused by persulfate salts is made by combining a clinical history, a diagnosis of asthma, and a positive skin prick test (SPT). Standardized methods for performing SPT with persulfate salts are warranted. A case of a young hairdresser with occupational asthma and hand eczema caused by persulfate salts is presented, and the procedure for performing the SPT with ammonium persulfate and potassium persulfate is described in detail.

Patch test dose-response study of p-phenylenediamine: thresholds and anatomical regional differences.

The elicitation response in allergic contact dermatitis for the hair dye substance p-phenylenediamine (PPD) is dose dependent, but threshold concentrations have not previously been investigated. 15 PPD-sensitive patients participated in a serial dilution 48-hr patch test with PPD using 8 concentrations of PPD ranging from 1 to 10 000 on the upper back. Petrolatum was applied as control. Three concentrations (50, 100 and 500 p.p.m. PPD) were also applied to the retroauricular area and on the lateral aspects of the upper arms. 14 of the 15 participants reacted to one or more of the test samples. The threshold value for 10% of the tested persons (ED10) based on+or stronger reactions for PPD on the back was 38 p.p.m. (CI: 4.3-100). There were no statistically significant differences in the sensitivity of the three anatomical regions. The upper back is a suitable region for patch testing patients with hair dye dermatitis.