Sensitization to disperse dyes in a patch test population over a five-year period.

BACKGROUND: In spite of sporadic data pointing at the role of textile dyes as important contact allergens, only few studies have addressed the issue of the frequency of sensitization to textile dyes in populations of consecutive patients. OBJECTIVE: The purpose of this study was to evaluate the prevalence of sensitization to disperse dyes, to investigate cross reactivity between azo dyes and para-amino compounds, to describe azo-dye-positive patients, and to study the correlation between clinical aspects and sensitization to different disperse dyes. METHODS: From January 1996 to December 2000, 6,478 consecutive patients were tested with 7 textile dyes: Disperse Blue 124, Disperse Blue 106, Disperse Red 1, Disperse Yellow 3, Disperse Orange 3 (DO3), para-aminoazobenzene (PAAB), and para-dimethylaminoazobenzene (PDAAB). RESULTS: Of the above, 437 patients were allergic. The most common sensitizers were Disperse Blue (DB) dyes and Disperse Orange 3. Both the clinical aspect and the localization of the lesions were unusual in a fair percentage of cases, especially in DB-positive subjects. Involvement of skin folds was observed in 27% of disperse dye-positive patients, mainly comprising DB-sensitive women. Cross-reactivity between azo-dyes and paraphenylenediamine (PPD) was frequent in DO3-, PAAB-, and PDAAB-positive subjects, but not in DB-allergic ones. Moreover, cross reactions between DB106 and DB124 were observed in 59% of DB106- and/or DB124-positive patients. CONCLUSIONS: The frequency of disperse dye allergy is higher than generally estimated. Further studies, using routine diagnostic testing with disperse dyes, are needed to investigate whether this increasing trend is present outside of Europe.     

Cross-sensitizations between azo dyes and para-amino compound

Combined sensitizations to different azo dyes, probably based both on true cross-sensitization and on simultaneous positive reactions, have frequently been described. However, since azo dyes are included in the standard series in a minority of countries, the case studies considered comprise, with few exceptions, a small number of subjects. The aim of our study was to investigate cross-reactions between different azo dyes and para-amino compounds in azo-dye-sensitive subjects, to study the clinical aspects of azo dye dermatitis, to assess the relevance of sensitization to azo dyes, and to relate the pattern of cross-sensitizations to the chemical structure of the different dyes. Out of 6203 consecutively tested patients, 236 were sensitized to at least 1 of 6 azo compounds employed as textile dyes, included in our standard series. 107 subjects reacted to Disperse Orange 3 (DO3), 104 to Disperse Blue 124 (DB124), 76 to p -aminoazobenzene (PAB), 67 to Disperse Red 1 (DR1), 42 to Disperse Yellow 3 (DY3), and 31 to p -dimethylaminoazobenzene (PDAAB). Co-sensitizations to para-phenylenediamine were present in most subjects sensitized to DO3 (66%) and PAAB (75%), in 27% and 36% of DR1 and DY3-sensitive subjects, and only in 16% of subjects sensitized to DB124. Apart from the hands and the face, the neck and the axillae were the most frequently involved skin sites. Whereas the involvement of flexural areas was mainly connected with sensitization to DB124, in patients with hand dermatitis and in those working as hairdressers, sensitization to DO3 and PAAB was more frequent. Moreover, in the former patient group, a history of textile dye allergy was most frequently obtained. Out of 33 patients tested with an additional textile dye series, only 5 subjects reacted to anthraquinone dyes. Cross-sensitizations between azo dyes and para-amino compounds can partially be explained on the basis of structural affinities.     

Chemical investigations of disperse dyes in patch test preparations

Background:  Contact allergy to textile dyes is not uncommon. The allergy is detected by patch testing patients with commercial patch test preparations.
Objective:  To investigate 8 disperse dyes (DDs) used for patch testing in the departments in Malmö and in Leuven and to compare them with test preparations used at various dermatology departments.
Materials/Methods:  The investigated DDs were Disperse Blue (DB) 35, 106, and 124, Disperse Yellow (DY) 3, Disperse Orange (DO) 1 and 3, and Disperse Red (DR) 1 and 17. From 13 clinics, 107 petrolatum preparations were analysed using high-performance liquid chromatography and thin-layer chromatography (TLC), and compared with reference substances obtained at the Malmö laboratory. Concerning DB 35, no reference substance could be identified.
Results:  TLC visualized impurities in all DDs. For each DD, except DB 35, the mean concentration in the preparations labelled to contain 1.0% (w/w) were DB 106: 0.30%, DB 124: 0.25%, DY 3: 0.44%, DO 1: 0.40%, DO 3: 0.68%, DR 1: 0.49%, and DR 17: 0.35%; there were variations between the samples also with regard to the number of impurities. DO 3 could not be demonstrated in 4/15 preparations labelled DO 3.
Conclusion:  The results may have implications for individual diagnosis and prevention and when comparing test results from various centres.     

FS01.1The use of azo dyes in the European Union – legislation review

Disperse blue 106 is one of the most important allergenic textile dyes. We reviewed all the patients that proved to be allergic to this dye, in 10 contact clinics, in Portugal, from 01/2000 to 06/2003. In the first 2 years disperse blue 106 was only tested in suspected cases, while in 2002/2003 it was routinely tested in our standard series. A total of 8957 patients (2797M + 6160F) were tested; fifty five patients (17M + 38F)(0.6%) were allergic to the dye, with a significant difference in incidence between the 2 periods (0.2 to 0.9%); a current relevance was found in 38 (69%) patients. In 5 patients the dermatitis was considered occupational. The main localizations were the axillae (25p), the antecubital fossae and the face (13p each), the neck (11p), the feet (8p), the hands and then trunk (7p each). Thirty six out of 44 patients (80%) that were tested with disperse blue 124 were allergic to this dye. Simultaneous reactions to PPDA and to fragrance mix were observed in 12 and 11 patients, respectively. Allergy to other dyes was found in 15 patients. Blouses and skirts were the main offending garments that induced contact allergy. Although both disperse blue 106 and 124 have been reported as frequent sensitizers, it proved not to be such an important allergen in Portugal. However, if tested routinely it can pick up some unexpected relevant allergic patients.     

Contact allergy to textile dyes in southern Sweden

Contact allergy to disperse dyes in textiles is documented in prevalence studies from southern Europe. To evaluate the prevalence of allergic patch test reactions to different textile dyes in southern Sweden, and to look at the sites of dermatitis in individuals hypersensitive to textile dyes, we retrospectively investigated 3325 consecutively patch-tested patients. They had all been patch tested with the standard test series supplemented with a textile dye mix (TDM) consisting of 8 disperse dyes, i.e. Disperse (D) Blue 35, 106 and 124, D Yellow 3, D Orange 1 and 3 and D Red 1 and 17. All but 3 of the TDM-positive patients were additionally tested with the separate dyes included in the mix. The frequency of contact allergy to TDM was 1.5%, which is comparable with studies from southern Europe. The most common dye allergen was D Orange 1. The high prevalence of allergic reactions to D Orange 1 was unexpected, whereas test reactions to D Blue 106 and 124 were lower than expected from other studies. Compared to all tested patients, the TDM-positive patients more often had dermatitis on their arms, face, neck and axillary folds, and women also had a higher frequency of hand dermatitis.     

Patch testing of patients allergic to Disperse Blue 106 and Disperse Blue 124 with thin-layer chromatograms and purified dyes

Background:  Former investigations have demonstrated that patch test preparations containing Disperse Blue (DB) 106 and DB 124 are impure.
Objective:  To investigate the significance of impurities in preparations of disperse dyes with regard to contact allergy.
Materials/methods:  21 patients allergic to DB 106 and/or DB 124 were tested with dilution series of commercial and purified DB 106 and DB 124. All patients were additionally tested with thin-layer chromatography (TLC) strips made from the commercial preparations containing DB 106 and 18 of them also with TLC strips containing DB 124.
Results:  13 of 21 and 12/18 patients tested positively to the strips of DB 106 and DB 124, respectively. Among these patients, 4/13 and 5/12, respectively, did not react to the main spot but reacted to other spots. Dilution series of purified DB 106 and DB 124 were positive in 10 patients each, while 16 and 15 patients, respectively, tested positively to the dilution series of the corresponding commercial disperse dye.
Conclusion:  Approximately 25% of the patients, diagnosed as contact allergic to DB 106 and DB 124, only reacted to impurities in the patch test preparations. This has implications for diagnosis and prevention.     

Textile dermatitis in Israel: a retrospective study.

BACKGROUND:The diagnosis of contact dermatitis caused by clothing may be difficult because of its clinical polymorphism. Data in the literature suggest that textile dermatitis is more common than previously thought. OBJECTIVE: Our purpose was to study our patients suspected of having textile contact dermatitis from 1991 to 1997. METHODS: The records of the patients with positive reactions to allergens from the Textile Colors and Finish series in 3 contact dermatitis clinics were reviewed. All the patients were clinically evaluated and patch tested with the European Standard series and the Textile Colors and Finish series (Chemotechnique Diagnostics, Malm?, Sweden). RESULTS: Twenty-two of the 55 patients (40%) had positive patch tests to the textile dye allergens. Four of them had occupationally related textile dermatitis. The most frequent allergens were Disperse Blue 124, Disperse Blue 85, Disperse Red 17, and Disperse Blue 106. Erythematosquamous lesions were the most common forms of textile dermatitis (56%), followed by pustular lesion (16%) and hyperpigmented patches (8%). CONCLUSIONS: The relatively high percentage of positive results (40%) was attributable to the selected cohort of patients. In our series, positive reactions to the allergens Disperse Blue 124, 85, and 106 were common findings. Clinically, pustular allergic contact dermatitis, triggered by textile dyes was observed along with the more frequent erythematosquamous clinical form.     

Contact sensitization to textile dyes: description of 100 subjects

We have described 100 subjects sensitized to textile dyes. Of these, 16 had clinically been suspected of having a textile dermatitis from among 1145 patients referred for patch testing. 41 patients were identified from among 861 consecutive subjects tested with the GIRDCA (Italian Research Group on Contact and Environmental Dermatitis) standard series supplemented with 4 disperse dyes (Disperse Blue 124, Disperse Red 1, Disperse Yellow 3, Disperse Orange 3). The remaining 43 patients were identified from among 746 subjects tested with the GIRDCA standard series, supplemented with the 4 disperse dyes mentioned above and a further series of 12 other textile dyes. The clinical picture was extremely variable: most patients had a typical eczematous dermatitis, but we also observed persistent erythematous-wheal-type reactions, a transient urticarial dermatitis and an erythema-multiforme-like eruption. Among these textile dyes, Disperse Blue 124 caused most reactions. With the addition of the 4 disperse dyes to the GIRDCA standard series, we identified 4.8% sensitized to textile dyes, a much higher figure than the 1.4% observed among patients being patch tested on the basis of their history and the clinical findings; the addition of a further 12 textile dyes to the series further increased the detection rate to 5.8%. We stress the importance of routinely patch testing with textile dyes, which can help to elucidate the cause of certain kinds of atypical dermatitis.     

Textile dermatitis in patients with contact sensitization in Israel: a 4-year prospective study

BACKGROUND: The exact incidence of textile dermatitis is unknown because of the lack of controlled epidemiological studies. Nevertheless, the increasing frequency of contact dermatitis to clothing has been demonstrated, thus indicating the importance of further investigations in this field. OBJECTIVE: To analyse the results from a 4-year prospective study of the clinical and aetiological features of contact dermatitis to textiles in Israel. We also aimed to assess the frequency and relevance of sensitization to textile dyes and resins in these patients. METHODS: Six hundred and forty-four patients (441 female and 203 male), referred for the investigation of contact dermatitis, and suspected of having textile allergic contact dermatitis (ACD), were studied. All patients were patch tested with the standard series (TRUE Tests), textile colour and finish series (TCFS) clothing extracts and pieces of garment in some cases. Readings were performed on days 2, 3 and in many patients also on day 7. RESULTS: Eighty-three patients (12.9%) had an allergic reactions to a dye and/or resin allergen. Of them, 43 (51.8%) had positive patch tests to the textile dye allergens, 28 (33.7%) to the formaldehyde and textile finish resins and 12 (14.4%) to allergens from both groups. The highest incidence of sensitization from the dye group allergens was due to Disperse Blue (DB) 124 (30.6%), DB 106 (27.0%) and DB 85 (8.1%) and from the resin group to melamine formaldehyde and ethyleneurea melamine formaldehyde (20.7% each) and urea formaldehyde (18.3%). Present relevance of the patch tests was found in 81.4% of the cases. Concomitant sensitization with allergens from the standard series included nickel sulphate, potassium dichromate, formaldehyde, rubber additives and others. Although chronic dermatitis was the typical clinical presentation, less frequent forms such as purpuric, hyperpigmented and papulopustular lesions and atypical forms such as erythema multiforme-like, nummular-like lesions, lichenification and erythrodermia were observed in 24.4% of the cases. The atypical manifestations were provoked by sensitization to dye allergens and never to resins. Along with the typical distribution in areas of friction on the trunk and extremities, less frequent areas including the hands, face, genital area and the soles were affected too. CONCLUSIONS: In view of the increasing frequency of contact dermatitis to clothing, the clinical assessment should include awareness of the classical as well as the unusual and atypical clinical forms and locations of ACD to textiles, for they are not infrequent. Although dyes and among them DB 106 and DB 124 are the most frequent allergens inducing textile dermatitis, concomitant testing with allergens from the textile dyes and resin groups is recommended when investigating patients with textile dermatitis.     

Disperse dyes in fabrics of patients patch-test-positive to disperse dyes.

BACKGROUND: Little evidence exists that dyes to which individuals are patch test positive are in those garments that they suspect cause their dermatitis, which makes diagnosis and management of colored-textile allergic contact dermatitis difficult. OBJECTIVE: We determined whether disperse dyes to which a patient suspected of having a colored garment-dye contact allergy were in the garment that the patient suspected to be the cause of his or her skin lesions. METHODS: Each patient was patch-tested with 12 disperse dyes in a commercial patch test series. Disperse dyes in the submitted garment(s) were identified. The dyes to which each patient was patch test positive were compared with the dyes identified in that patient's submitted fabric(s). When a dye appeared in both lists, a correlation was found. RESULTS: Twenty-two of 32 garments received contained disperse dyes. In all, 35 different disperse dyes were identified. Twelve dyes elicited a reaction in at least one patient. Only nine patients were patch test positive to at least one dye identified in the fabric submitted. Dyes appearing in both lists were Blue 106 (8 times), Blue 124 (2 times), Yellow 3 (once), and Red 1 (once). CONCLUSION: Dyes to which a patient was patch test positive were infrequently identified in the fabric suspected to be the cause of the skin lesions, which means that the next step will be to patch-test with fabric swatches and extracts of dye from the submitted garments.     

Disperse blue dyes 106 and 124 are common causes of textile dermatitis and should serve as screening allergens for this condition.

BACKGROUND:Textile dye dermatitis is frequently undiagnosed because clinical awareness is low and because of the absence of good screening allergens in standard patch test series for this type of contact dermatitis. OBJECTIVES: To determine the incidence of textile dye allergy in patients with problematic eczemas evaluated at a contact dermatitis clinic, and to determine the incidence of allergic contact dermatitis to diperse blue dyes in these patients. METHODS: We conducted a retrospective study of 788 patients who were patch tested to either the North American Contact Dermatitis Group (NACDG) Standard Series or the European Standard Series, in addition to other relevant series. The Chemotechnique textile series was utilized in 271 patients (28%). RESULTS: Forty patients reacted positively to 1 or more textile dyes, the majority reacting positively to Disperse Blue 106 (33 of 40; 82.5%) and to Disperse Blue 124 (32 of 40; 80%). Ten of 11 tested patients reacted to their own clothing, 9 of whom reacted to the blue/black 100% acetate or 100% polyester liners in their garments. CONCLUSIONS: Textile dye allergy is more common than previously reported. It can cause marked dermatitis and widespread autoeczematization reactions. The most frequent allergens are Disperse Blue 106 and 124, which are frequently found in the 100% acetate and 100% polyester liners of women's clothing. We recommend that Disperse Blue 106 or 124 serve as the screening allergen for textile dye dermatitis.     

Chronic generalized eczema caused by multiple dye sensitization

Textile dye sensitization is rare; its low incidence (1.4% to 5.8%) is most likely because dye contact allergy is not suspected and therefore not tested. The greatest number of positive test results are obtained for disperse dyes. We report an uncommon observation of severe and chronic textile dye dermatitis with positive patch test results to Disperse Blue 106, Disperse Blue 124, Disperse Brown 1, Disperse Yellow 3, and p-aminophenol. p-aminophenol, Disperse Blue 124, and Disperse Blue 106 are derived from p-phenylenediamine, but this allergen seems to be unreliable as a detector of textile dye allergy. The admittedly allergic capacity of disperse dyes and the increasing fabrication of synthetic fibers (acrylics and polyesters) usually colored with this group of dyes could induce more frequent textile sensitization.     

Patch testing with the textile dyes Disperse Orange 1 and Disperse Yellow 3 and some of their potential metabolites, and simultaneous reactions to para-amino compounds

Background. It is known that, in vitro, human skin bacteria are able to split disperse azo dyes into the corresponding aromatic amines, some of which are sensitizers in the local lymph node assay. We hypothesize that the molecules of disperse dyes migrate onto the skin while garments are worn, and are metabolized and degraded by commensal skin bacteria. These molecules penetrate the skin and induce sensitization. Objectives. To evaluate the elicitation capacities of the possible azo-degradation products of the selected azo disperse dyes in patients allergic to them and to compare it with the elicitation capacities of other para-compunds. Methods. Ten patients allergic to Disperse Yellow 3 (DY3) and/or Disperse Orange 1 (DO1) were patch tested with a dilution series of the purified dyes 4-nitroaniline and p-aminodiphenylamine in concentrations equimolar to those of purified DO1 in the dilution series, as well as 4-aminoacetanilide and 2-amino-p-cresol in concentrations equimolar to those of purified DY3 in the dilution series. Results. Three patterns of patch test reactions could be seen. The 6 patients who were positive to DO1 and DY3 also reacted to p-aminodiphenylamine and 2-amino-p-cresol. Two patients were positive to DO1 only, and both reacted to p-aminodiphenylamine, but to neither 4-aminoacetanilide or 2-amino-p-cresol. Two patients did not react to DO1 or DY3 on this occasion. Conclusion. We show that it is possible that the major sensitizers in contact allergy to DO1 and DY3 are their metabolites, p-aminodiphenylamine and 2-amino-p-cresol, respectively, which might be formed by the azoreductase pathway of skin bacteria.     

Contact allergy to Disperse Blue 106 and Blue 124 in black "velvet" clothes

9 cases of allergic contact dermatitis due to black "velvet" fabrics, mostly leggings, are reported. In all cases, the 2 disperse dyes Blue 106 and 124 were shown to be the responsible contact sensitizers. Preparation of a chloroform extract and separation of the different disperse dyes by analytical and preparative thin-layer chromatography showed that 8 of the 9 black "velvet" clothes contained the same composition, namely Disperse Blue 1, 106, and 124, Disperse Red 1 and Disperse Yellow 3. In experimental studies performed previously. Disperse Blue 124 has been demonstrated to be a moderate sensitizer while Disperse Blue 106 proved to be the strongest found so far among the azo disperse dyes.     

Multiple azo disperse dye sensitization mainly due to group sensitizations to azo dyes

A female patient, with a previous episode of contact dermatitis caused by a blue dress developed similar dermatitis due to a navy -blue dress. Patch tests revealed multiple allergic positive reactions to paraphenylenediamine (PPD). The navy-blue dress, its extracts, 6 azo disperse dyes in a textile series, as well as 3 dye components, including Disperse (DP) Red 153, which were present in the dress: these were composed of 9 azo disperse dyes, all dyes being of a different chemical structure. On the basis of chemical similarities between these 16 azo dyes including PPD, these are classified into the following 4 groups: thiazol-azoyl-PPD group (including DP Blue 106. DP Blue 12-1 and 5 used dyes), aminoazobenzene group (DP Red 1. DP Red 17. DP Brown 1 and 2 used dyes). PPD group (PPD and DP Orange 3) and benzothiazol-azoyl-PPD group (2 dyes in DP Red 153). With few exceptions, cross-sensitizations between dyes in the same group have been reported by other authors, or are suggested by us, in the former 3 groups. Multiple azo disperse dye sensitization is therefore considered lo be attributable mainly to group sensitizations to azo dyes.)     

Is PPD a useful screening agent?

In this study, the usefulness was assessed of para-phenylenediamine (PPD) base as a marker for contact allergy to para-compounds and disperse dyes. 59 patients with a positive reaction to PPD were patch tested with a series of para compounds and disperse dyes. This dyes series was also tested in patients with a suspect medical history of contact allergy to hair, fabric or leather dyes. In total 610 patients were tested. As 24 patients became positive over the weekend, late readings, day 6 or 7, are important. These reactions were most probably relevant in 17/24 patients. Positive reactions to PPD correlated well with reactions to para compounds like p-aminoazobenzene and p-toluenediamine sulphate but not with disperse dyes. Reactions to Disperse Blue (106, 124) and Orange (1 and 3) were seen most frequently. PPD is a good screening agent for hair dye, but not for disperse dye, sensitivity.     

Contact allergy to Disperse Blue 106 and Disperse Blue 124 in German and Austrian patients, 1995 to 1999

Between 1995 and 1999, 1986 patients were tested in the 31 participating centres of the Information Network of Departments of Dermatology (IVDK), all of them members of the German Contact Dermatitis Research Group, with a textile dyes series containing Disperse Blue (DB) 106 and 124, and since 1997 also with a mix of both. 86 patients (4.3%) reacted positively to DB 106 and/or DB 124; with good concordance between the 2 allergens (Cohen's weighted kappa 0.72), and the single allergens and the mix (kappa=0.75 in both cases), which had been tested in parallel in 969 and 975 patients, respectively. In contrast, concordance between DB 106/124 and p-phenylenediamine and p-aminoazobenzene, respectively, was poor. Some 70% of positive reactions to DB 106/124 had current clinical relevance. Furthermore, a significant increase in the proportion of DB 106/124-positive patients among those tested was found from 1995 to 1999. Hence, DB 106/124 are important allergens deserving close monitoring. The use of a mix of DB 106 and DB 124 seems justified in view of the close chemical similarity of both compounds. If possible, the presence of the allergen(s) in individual textiles considered causative should be checked by thin layer or column chromatography.     

Patch testing in infants

The aim of this study was to evaluate the frequency of contact sensitization in infancy because very few data on this topic are available in the literature. We patch tested 53 children, ranging in age from 3 months to 2 years, admitted to our allergological outpatient department for eczematous dermatitis with the Italian Research Group on Contact and Environmental Dermatitis standard series. Thirty-nine of the 53 patients were affected by atopic dermatitis. Thirty-two patients (60%) showed positivities to patch tests; 16 of these were polysensitized. Twenty-five of the contact-sensitized children had atopic dermatitis. The haptens responsible for the highest number of positivities were thimerosal and nickel, followed by ammoniated mercury, disperse dyes, fragrances, and preservatives. Our results stress the importance of patch testing patients with atopic dermatitis or suspected contact dermatitis younger than 2 years of age.     

Occupational contact dermatitis to textile dyes in airline personnel.

BACKGROUND: Reports of textile dye allergic contact dermatitis are becoming frequent in the literature. Occupational exposure to textile dyes has been reported, but less frequently. OBJECTIVE: To report 2 cases of allergic contact dermatitis to Disperse Blue dyes 106 and 124 occurring in airline personnel. METHODS: The patients were patch tested to the European or North American standard series, a textile dye series, and 1 patient was tested with pieces of textile from an airplane seat. RESULTS: Patch testing elicited in both patients a 2+ reaction to Disperse Blue dyes 106 and 124, and a 1+ reaction to paraphenylenediamine in one patient. CONCLUSION: We describe 2 cases of occupational textile dye allergy occurring in airline personnel. Both cases showed the utility of Disperse Blue dyes 106 and 124 to serve as the screening allergens for textile dermatitis. Mandatory uniforms might be an occupational hazard in certain professions.     

Contact allergy from disperse dyes in textiles–a review

Several disperse dyes (DDs) are still considered to be the most important allergens in textile dermatitis, but there are sparse data about their current use in textiles. The aim of this review was to evaluate published studies and reports on contact allergy to DDs published in PubMed during the last 22 years (1990–2012). Prevalence data are provided by study and by dye, as well as by the described clinical peculiarities of DD dermatitis. We reviewed 54 studies. In total, 26 DDs were tested. The average prevalence in screening studies was >1% for Disperse Blue 106, Disperse Blue 124, and Disperse Orange 3. There is a lack of data on patch testing with Disperse Blue 26, Disperse Blue 102, Disperse Orange 37, Disperse Orange 149, Disperse Yellow 23 and Disperse Yellow 49, which are listed as allergens by the EU Commission. It is necessary to check the purity and identity of dyes used for patch testing, confirm the clinical relevance of positive reactions by patch testing with suspected textiles, and, if the results are positive, determine the culprit dye.