The diagnostic value of atopy patch testing and prick testing in atopic dermatitis: facts and controversies

We conducted a systematic Medline search of the literature (1998-2008) on the criteria for performing the skin prick test and atopy patch testing (APT) to determine their utility in atopic dermatitis (AD). The skin prick, scratch, and skin patch tests are performed to identify which allergen is causing eczematous skin symptoms in patients with AD, or sneezing, nasal congestion, itchy eyes, wheezing, skin rash, and swelling. Many allergens in foods, drugs, and environmental substances (eg, ragweed and fungus), as well as contact allergens, can elicit eczematous skin reactions after epicutaneous application. Because no gold standard exists for aeroallergen provocation in AD, the APT is currently used to evaluate allergen without comparison with another accurate and reliable method. The APT is presumed to reflect delayed-phase clinical reactions. Even with delayed onset of symptoms (more than 2 hours after food ingestion), APT findings were not consistent among AD children. The APT could be used in children with gastrointestinal reactions to foods as well as AD. After standardization, the APT may provide further diagnostic information in addition to the skin prick test and serum immunoglobulin E values and may be able to evaluate the actual clinical relevance of immunoglobulin E-mediated sensitizations for eczematous lesions. The European APT model used with standardization of allergen concentration and vehicle may provide an important diagnostic tool to select patients for avoidance and for procedures of allergen-specific immunotherapy, but the clinical relevance of positive APT reactions awaits standardized provocation and avoidance testing.     

Parthenium dermatitis presenting as photosensitive lichenoid eruption. A new clinical variant

Parthenium hysterophorus is the commonest cause of airborne contact dermatitis (ABCD) in India. The disease usually manifests as itchy erythematous, papular, papulovesicular and plaque lesions on exposed areas of the body. Rarely, however, the disease may present as actinic reticuloid or photocontact dermatitis. We have observed a different clinical variant of this disease where certain patients with Parthenium dermatitis have presented with discrete, flat, violaceous papules and plaques on exposed areas of the body closely simulating photosensitive lichenoid eruption. We had 8 patients, 6 males and 2 females between 30 and 62 years of age, with itchy, violaceous, papules and plaques on the face, neck, ears, upper chest and dorsa of the hands for 6 months to 6.5 years. Four of these patients had a history of improvement of the lesions up to 30% in winter and aggravation of lesions on exposure to sunlight. There was no personal or family history of atopy. Cutaneous examination in all patients revealed multiple flat, violaceous, mildly erythematous papules and plaques on the forehead, sides and nape of neck, ears, 'V' area of the chest, and extensor aspects of the forearms and hands. Skin biopsies from these lesions showed features of chronic non-specific dermatitis. Patch testing with standardized plant antigens showed a positive patch test reaction to Parthenium hysterophorus in all patients, with a titre of contact hypersensitivity (TCH) varying from undiluted to 1 : 100. We conclude that Parthenium dermatitis may occasionally present with lesions very similar to the lesions of photosensitive lichenoid eruption in morphology and distribution. This clinical presentation of Parthenium dermatitis needs to be recognized to avoid misdiagnosis.     

The frequency of contact allergy in atopic patients with dermatitis

A prospective study was performed to establish the frequency of contact allergy in atopic patients presenting with dermatitis, compared with non-atopics suffering from dermatitis. During 1987-1988, all new patients aged 15 years or older, who consulted us for dermatitis, were investigated. They were patch tested with the European standard series, methyl(chloro)isothiazolinone and other relevant allergens. In addition, they were prick tested with 24 inhalant and 11 food allergens. Patients having at least 2 positive prick tests, and patients with 1 positive prick test and a (family) history of atopic diseases were defined as atopics, as were those who presented with classic atopic dermatitis but with negative prick tests. 499 patients were evaluated: 159 men and 340 women. 214 patients (43%) were atopic, the other 285 (57%) were non-atopic. In the atopic group, 79 persons (37%) had at least 1 positive patch test reaction. In the group of non-atopics, 149 patients (52%) had contact allergies. The difference is statistically significant (chi 2; p less than 0.05). It is concluded that adult atopics seen in dermatological practice who present with dermatitis are less frequently contact sensitized than such patients who are non-atopic. Nevertheless, a yield of nearly 40% positive patch test reactions in this group still makes routine patch testing necessary.     

Allergic contact dermatitis from natural latex.

BACKGROUND: Reports on natural latex allergy have increased steadily during the last 10 years. Latex allergy generally refers to a type 1 reaction to natural rubber latex (NRL) proteins with clinical manifestations ranging from contact urticaria to asthma and anaphylaxis. Previous United States studies on NRL allergy largely have been reported by allergists with little detailed information on hand eczema, contact allergy, or on outcome. The present study was performed from March 1998 to November 1999 with the aim of finding out the prevalence of type IV hypersensitivity to latex in patients with suspected rubber allergy. MATERIALS AND METHODS: A total of 167 patients with hand eczema and contact with rubber products underwent patch testing with the standard screening and rubber components (test series Deutsche Kontaktallergiegruppe), and NRL pure provided by Regent (liquid high ammonia 0.7% NRL, accelerator, and preservative-free latex) between March 1998 and November 1999. The charts of all NRL positive patients are reported with the results of history, prick, patch tests, total IgE, specific IgE to latex (FEIA) test and follow-up data (after 6 months). RESULTS: Four patients (3 men) showed positive patch test results to NRL. One of these patients also reacted to the rubber chemical tetraethylthiuram monosulfide, and another one of these patients revealed a type 1 reaction to NRL, diagnosed by positive reaction to prick test. The other 3 patients with patch test reactions to NRL had negative reactions to prick tests to NRL extracts after 20 minutes. All 4 patients had a positive delayed prick test reaction to NRL. Latex FEIA test result was negative in all 4 patients. The contact eczema healed after elimination of the latex gloves and medical latex devices in all patients. Furthermore, 10 of the 167 patch testing patients (6%) were positive for tetramethylthiuram monosulfide 1%. CONCLUSION: In the present study with 167 patients, the prevalence of type IV hypersensitivity to latex was 2.4%. We recommend that the patch test with NRL as well as with rubber additives should be performed in patients of suspected contact dermatitis caused by rubber products.     

Positive atopy patch test reaction to Malassezia furfur in atopic dermatitis correlates with a T helper 2-like peripheral blood mononuclear cells response

The yeast Malassezia furfur belongs to the normal cutaneous flora, but is also a triggering allergen that can contribute to atopic dermatitis. To illuminate the effect of circulating allergen-specific T cells in atopic dermatitis, the peripheral mononuclear cell response was correlated with the in vivo skin prick test and atopy patch test reactivity to M. furfur. None of 16 healthy controls showed any positive in vivo reaction. The 40 atopic dermatitis patients, of whom 18 had serum IgE reactivity to M. furfur, were subdivided according to their in vivo reaction to M. furfur extract into three groups: skin prick test positive/atopy patch test positive (n = 12), skin prick test positive/atopy patch test negative (n = 12), and skin prick test negative/atopy patch test negative (n = 16). The skin prick test positive/atopy patch test positive and the skin prick test positive/atopy patch test negative groups had a significantly higher peripheral mononuclear cell stimulation index than the healthy controls. Interestingly, the stimulation index values in the skin prick test positive/atopy patch test positive group were significantly higher than in the skin prick test positive/atopy patch test negative group. In the M. furfur skin prick test positive atopic dermatitis patients (n = 24) a correlation was found between stimulation index and the M. furfur atopy patch test reactions, but not between stimulation index and M. furfur-specific serum IgE levels. Skin prick test positive and/or atopy patch test positive reactions to the recombinant M. furfur allergens rMal f 1, rMal f 5, and rMal f 6 were observed in 7, 14, and 16 of the 40 atopic dermatitis patients, respectively. Further, there was a correlation between production of the T helper 2-related cytokines interleukins 4, 5, and 13 and stimulation index to M. furfur extract, but not between the T helper 1-related interferon-gamma and stimulation index to M. furfur extract. Our data strongly suggest a relationship between circulating specific T cells with a T helper 2-like cytokine profile and positive atopy patch test reactions.     

皮炎湿疹的速发型和迟发型变态反应检测分析

目的探讨对皮炎湿疹患者同时进行速发型和迟发型变态反应检测的必要性。方法对2007年3月～2009年3月间同时进行斑贴试验和点刺试验检查的复发性皮炎湿疹患者进行回顾性分析。结果212例同时进行斑贴试验和点刺试验检查的复发性皮炎湿疹患者中斑贴试验有一项或一项以上过敏原阳性者106例,阳性率为50.00%,阳性率最高的前三位过敏原为重铬酸钾(61/212)、硫酸镍(18/212)和甲醛(15/212)。点刺试验有一项或一项以上过敏原阳性者98例,阳性率为46.23%,阳性率最高的前三位过敏原为屋尘螨(46/212)、粉尘螨(42/212)和红辣椒(24/212);斑贴和点刺试验均有一项或一项以上过敏原阳性者42例,占总人数的19.81%,占斑贴试验阳性者的39.62%,占点刺试验阳性者的42.86%。结论为更好地筛查和有效避免变应原,有必要对反复发作的皮炎湿疹患者同时进行速发型和迟发型变态反应检查。     

Contact allergy to aeroallergens in children with atopic dermatitis: comparison with allergic contact dermatitis

Immediate and delayed cutaneous hypersensitivity are believed to be implicated in the physiopathology atopic dermatitis (AD). The purpose of this study was to evaluate Type I and Type IV allergy to aeroallergens in children with AD. 59 children (mean age 5.2 years), presenting with AD according to Hanifin and Rajka's criteria, were skin tested (patch and corresponding prick tests) with common environmental aeroallergens and a restricted panel of the European standard series over a 1-year period. History and clinical data were carefully recorded using a standardized evaluation sheet: total and specific IgE serum levels were evaluated 17 of 59 patients (28.8%) had at least 1 positive patch test, 32 of 59 patients (54.2%) had at least 1 positive prick test. Corresponding patch and prick tests were observed in 8 out of 17 patients. 5 children with positive patch tests had negative prick tests. Irritant pustular reactions (2/59, i.e. 3%), "angry back" reactions (6/59, i.e. 10%) and doubtful reactions (3/59, i.e. 5%) were excluded from the positive group. Positive patch tests observed included, in decreasing order: D. pteronyssinus and D. farinæ (26.8%) garden trees (12.2%), plantain (9.8%), timothy grass, mugwort and damp area trees (4.9% each), and orchard grass (2.44%). 6 children with positive aeroallergen patch tests and 11 children with negative aeroallergen patch tests had at least 1 positive patch test to standard allergens. All children with an irritant reaction to aeroallergens had no reaction to standard patch tests. The relevance of aeroallergens in upgrading the severity of AD lesions has still to be explored by challenge studies and by long-term follow-up.     

先天性色素痣伴增生性结节10例临床病理分析

【摘要】 目的 探讨先天性色素痣伴增生性结节的临床特点及组织病理特征。方法 收集第四军医大学西京皮肤医院2015—2019年经临床和病理确诊的10例先天性色素痣伴增生性结节患者的临床及病理资料，并进行回顾性分析。结果 10例患者年龄2～45岁（平均15岁），9例增生性结节发生于婴儿，1例发生于成人。皮损位于四肢4例，头面部3例，躯干2例，躯干及四肢同时受累1例。临床表现为黑色斑片或斑块中出现1个或多个结节，6例增生性结节为多发，4例为单发，单个结节直径0.2～1.5 cm，仅1例出现溃疡。组织病理检查显示增生性结节内黑素细胞均存在成熟现象，核分裂象少，细胞无明显异型性，无坏死现象，免疫组化检查显示痣细胞弥漫表达Melan-A，不表达或仅部分表达HMB45，Ki67增殖指数 < 5%。结论 先天性色素痣伴增生性结节可发生于四肢、头面部及躯干；临床表现为原先天性色素痣皮损上的单发或多发结节；病理上增生性结节内黑素细胞可见成熟现象，免疫组化HMB45及Ki67染色有助于诊断，其预后有待长期随访。     

Type IV hypersensitivity reactions to natural rubber latex: results of a multicentre study

BACKGROUND: Positive patch test reactions to natural rubber latex (NRL) have been interpreted as allergic or irritant by different groups. Additives to the NRL test solution have also caused positive reactions in previous studies. OBJECTIVES: Five centres of the British Contact Dermatitis Group conducted a prospective study on the prevalence of type IV hypersensitivity to NRL, using ammonia-preserved NRL solution for testing. PATIENTS AND METHODS: A total of 2738 consecutive patients were patch tested. Where clinically indicated, specific IgE was measured or a prick test done. RESULTS: Twenty-seven patients (1%) had a positive patch test reaction to NRL, which was considered to be allergic and of current relevance in 19 (70%) patients. Fourteen of these also had a positive prick test or specific IgE. Thirteen patients (48%) were male, 19 (70%) atopic and 13 (48%) had eczema on their hands. CONCLUSIONS: We conclude that delayed-type hypersensitivity to NRL is a problem for a proportion of patients with eczema, particularly on their hands, and that patch testing with ammonia-preserved NRL can be recommended to identify these patients. Patients with a positive patch test should be investigated for contact urticaria to NRL.     

Atopy patch test reactions to house dust mites in patients with scabies

It is well known that the house dust and the scabies mites are related phylogenetically. We therefore performed atopy patch tests with house dust mite antigens (Dermatophagoides pteronyssinus (Dp) and/or Dermatophagoides farinae (Df)) in scabies patients without atopy and healthy controls. We studied 25 men with active scabies and 25 healthy controls. Skin prick tests with standardized house dust mite extract were performed for all patients and controls. An intradermal test procedure was carried out in skin prick test-negative patients, and for controls showing positive atopy patch test to Dp and/or Df. While atopy patch tests were performed directly in all healthy controls, patients with scabies were first treated and on the next day, atopy patch tests were performed. Twenty-two of 25 patients with scabies (88%) had skin prick test and/or intradermal test positivity against house dust mites, whereas 17/25 patients (68%) had atopy patch test positivity against house dust mites (Dp and/or Df). There was no statistically significant difference between skin prick test and/or intradermal test positivity and atopy patch test positivity in a regression analysis (p=0.222). The only statistically significant correlation was between atopy patch test positivity and the extent of scabies involvement (p<0.05). Only few of the healthy controls had positive tests. In this study, we have shown that a positive atopy patch test to house dust mite antigens is not specific for patients with atopic dermatitis, but also occurs in scabies patients without a history of atopic dermatitis.     

Platinum in the environment: frequency of reactions to platinum-group elements in patients with dermatitis and urticaria

The aim of the present paper is to evaluate whether increasing environmental exposure increases the frequency of the positive prick and patch test reactions to certain chlorinated platinum salts in patients with dermatitis and urticaria. 800 consecutive subjects with contact dermatitis (n=749) and urticaria (n=51) were variously patch and prick tested with 30 haptens of a standard series, with aqueous solutions of, respectively, hexachloroplatinic acid (H2[PtCl6]), potassium tetrachloroplatinate (K2[PtCl4]), sodium hexachloroplatinate (Na2[PtCl6]), iridium chloride (IrCl3), rhodium chloride (RhCl3) and palladium chloride (PdCl2), and with 16 common inhalants. 153 workers, variably exposed in a platinum refinery, were patch and prick tested only with solutions containing platinum-group elements at various concentrations and with 16 common inhalants. Platinum-group elements did not elicit positive patch or prick test reactions in non-occupationally exposed subjects. In contrast, in exposed workers, positive patch test reactions at day 2 and at 25 min, respectively, were found in 2 subjects with hand dermatitis and in 2 with urticaria and asthma. 22 out of the 153 workers, 18 of whom had rhinitis, asthma, and urticaria, gave positive prick test reactions to 1 or more salts. Furthermore, on patch and prick testing, 4 cross-reactions between platinum, palladium, iridium and rhodium were demonstrated. In conclusion, the test results demonstrate that the present concentration in the environment does not increase the incidence of reactions to platinum salts in patients with dermatitis and/or urticaria. However, if the average level of environmental platinum exposure approaches those existing in industrial settings in the future, we are going to observe more frequent health effects.     

Patch testing with egg represents a useful integration to diagnosis of egg allergy in children with atopic dermatitis

Our aim was to investigate atopy patch and skin prick test reactions to egg in 85 children with atopic dermatitis, and to evaluate their relevance by performing repeated open challenges with egg. Thirty-one percent of our patients showed an eczematous response to the challenge. Positive reactions to atopy patch and skin prick tests were recorded in 37% and 19%, respectively. Atopy patch test sensitivity proved significantly higher than that of skin prick test (79.6% vs. 46.2%), whereas specificity was lower (81.4% vs. 93.2%). Our data suggest that combined skin prick and patch testing improves screening for egg allergy in affected children, identifying 92% of those who were challenge positive among our patients.     

Occupational food-related hand dermatoses seen over a 10-year period

Background. Protein contact dermatitis was originally defined in 1976 by Hjorth and Roed‐Petersen as a distinct kind of dermatitis seen in patients with occupational food contact. Even though occupational skin diseases are frequent in Denmark, little attention has been paid to protein contact dermatitis, and the frequency is unknown. Objectives. To evaluate the frequency of occupational food‐related hand dermatoses and test results in patients occupationally exposed to foods. Materials and Methods. This was a retrospective study based on examinations, including skin prick testing and patch testing, performed at the Department of Dermato‐Allergology, Gentofte University Hospital, Denmark between 2001 and 2010. Results. Of all patients (n = 372), 57.0% had irritant contact dermatitis, 22.0% had protein contact dermatitis, 2.4% had contact urticaria, and 1.8% had allergic contact dermatitis. A suggestion for diagnostic criteria is presented. Frequent risk occupations were cooking in restaurants, baking, and kitchen work. Substantially more patients reacted in skin prick testing with fresh foods than with food extracts. Conclusion. Protein contact dermatitis is a frequent disorder among patients who professionally handle foods, and should be considered to be a distinct clinical entity. When diagnosing protein contact dermatitis and in other food‐related skin prick testing procedures, it is important to include fresh foods.     

Allergic contact dermatitis from hair dye and development of lichen simplex chronicus

Those who dye their hair frequently manifest allergic contact dermatitis (ACD) from p-phenylenediamine (PPD)-containing hair dye. PPD is known to be the most frequent sensitizer in hair dye, but there has been no documentation of this sensitizer having a role in chronic dermatologic conditions. Our department experienced a case of a 62-year-old woman with lichen simplex chronicus (LSC), who complained of aggravation after hair dyeing and made such an association. We conducted a prospective and retrospective study to further evaluate the clinical associations between the two. In our prospective study, patch testing was performed in selected patients who regularly carried out hair dyeing and also had clinical manifestations of LSC. Also a retrospective examination was conducted in cases where patch testing had been performed with PPD in the past for suspected ACD and further selected cases with concurrent LSC and/or other neurodermatitis. 11 and 14 patients in our prospective and retrospective study, respectively, presented with both LSC and positive findings to PPD. 5 (45.5%) and 4 (28.6%) patients in our prospective and retrospective study showed clinical relevance from clinical improvement after stopping use and rechallenge. We report several cases of patients diagnosed as having LSC and/or prurigo nodularis who showed clinical improvement after discontinuing the use of hair dye. The suggestion can therefore be made that hair dye could be a possible aetiologic agent causing LSC in those using hair dyes.     

Lichen Planus Pemphigoides Presenting Preferentially Over Preexisting Scars: A Rare Instance of Isotopic Phenomenon

An 18-year-old girl presented with multiple itchy hyperpigmented papules and plaques, along with tense blisters over the lower limbs and buttocks for last 3 months. These papules, plaques, and bullae were mostly localized to preexisting scars. The histopathological findings from papule and bulla were consistent with lichen planus (LP) and bullous pemphigoid, respectively. Direct immunofluorescence (DIF) of perilesional skin around bulla showed linear deposition of IgG and C3. Considering clinical, histopathological and DIF findings, diagnosis of LP pemphigoides (LPP) was made. The preferential localization of LPP lesions over preexisting scars was a very interesting finding in our case an extremely rare instance of the isotopic phenomenon.     

Allergy to local anesthetics: Comparison of patch test with prick and intradermal test results

The interrelation between immediate and delayed hypersensitivity reactions to local anesthetics is poorly understood. Especially, the relevance of positive patch test reactions to local anesthetics with regard to the compatibility of injected local anesthetics is unclear. We therefore subjected 104 patch test-positive probands to prick and intradermal tests with seven local anesthetic agents. All prick tests were negative. Only 14 patients showed positive reactions in intradermal tests: 11 with the ester local anesthetic procaine, one with the amide local anesthetic butanilicaine, and two with both. Procaine yielded both immediate and delayed reactions; butanilicaine, only immediate reactions. All other local anesthetics showed negative reactions. It is concluded that in patients with positive patch test reactions to local anesthetics and negative history of anaphylactoid reactions, positive skin test reactions to intradermal application are rare and that, therefore, the risk of anaphylactic reactions to injection anesthesia with amide local anesthetics, except butanilicaine, appears low in these patients.     

Cicatricial alopecia; a dermatopathologic and immunopathologic study of 33 patients (pseudopelade of Brocq is not a specific clinico-pathologic entity)

BACKGROUND: Pseudopelade of Brocq (PB) is a permanent progressive scarring alopecia characterized by numerous alopecic patches localized only in the scalp, that tend to coalesce into larger, irregular plaques with policyclic borders. PB can be considered either the final atrophic stage of several scarring disorders such as lichen planus pilaris (LPP) and discoid lupus erythematosus (DLE) (secondary PB) or an autonomous disease (primary PB). The aim of this study was to assess the incidence of primary vs. secondary PB by a combined histopathological and immunopathological study in a series of patients who fulfilled the clinical diagnostic criteria for PB set forth by Braun Falco et al. METHODS: We studied 33 patients (5 males and 28 females, whose age ranged from 24 to 75 years). The duration of the disease (from onset to biopsy) ranged from 3 months to 8 years. Serum samples were tested for circulating auto-antibodies (antinuclear antibodies anti ENA, anticentromere, anti-Scl70, antithyroid, antigastric parietal cells) circulating immune complexes, total and single fraction (C3, C4) complement activity. The skin biopsies taken from the active advancing margin of the more recent alopecic patch were bisected vertically, one was sent for histopathological examination, and the other for the immunofluorescence studies. RESULTS: In all patients the serum tests above were found to be negative or normal. Histopathologically, 11 biopsies (33.3%) displayed findings typical for LPP whereas seven cases (21.2%) showed typical DLE features. In the remaining 15 cases (45.5%) histopathological findings were not suggestive of any specific dermatosis. DIF investigations showed findings typical of LPP in six cases (18.1%) and typical of DLE in seven cases (21%). In three cases we did not find findings typical of LPP, DLE, or any other specific dermatitis. In 11 cases no immunological deposits could be detected and therefore were classified as negative. CONCLUSION: In conclusion, PB is a type of scarring alopecia of the scalp associated with a peculiar clinical presentation and evolution, which cannot be considered an autonomous nosologic entity because in 66.6% of patients it is the end stage of other inflammatory chronic diseases such as LPP and DLE. It is conceivable that even in those cases in which the histopathological and immunopathological findings did not allow for a specific diagnosis, LPP and DLE were also involved. It is noteworthy that in our study the histopathological and the immunopathological examinations did not conflict and often the results were even coincidental, thus confirming the compatibility of the combined histo-immunopathological approach in the diagnostic evaluation of PB.     

斑秃伴白癜风和盘状红斑狼疮1例

报告1例斑秃伴白癜风和盘状红斑狼疮,患者男,67岁。临床表现为头顶、两颞侧头皮片状脱发,头顶脱发区边缘出现片状白斑,面颊部两侧,耳后见境界清楚的紫红色丘疹、斑块,表面有粘着性鳞屑,鳞屑下方有角栓。结合临床和组织病理改变诊断为斑秃伴白癜风和盘状红斑狼疮。     

Analysis of para-phenylenediamine allergic patients in relation to strength of patch test reaction

BACKGROUND: Despite having a positive patch test reaction to para-phenylenediamine (PPD), some patients continue to dye their hair, while others are forced to give up or abandon this practice. This difference in patient behaviour could be due to the degree of sensitization. OBJECTIVES: To establish whether the ability to continue dyeing hair in PPD allergic patients is related to the strength of patch test reaction. To note differences in other clinical features in relation to the strength of patch test reaction. METHODS: We analysed retrospectively the patch test records of 400 sequential PPD-positive patients for the strength of patch test reaction (+, ++, +++) and different clinical features. Data were analysed using Cochran-Mantel-Haenszel chi2 tests. RESULTS: There was a strong linear relationship between the strength of patch test reaction and continuation with hair dyeing. Patients were more likely to report a history of hair dye reaction with increasing strength of patch test reaction. There was no difference in strength of patch test reaction in relation to age, site of rash, occupation (hairdressing) or history of atopic eczema. Overall concomitant reactivity with related aromatic amine allergens (benzocaine, N-isopropyl-N-phenyl-para-phenylenediamine, para-aminobenzoic acid) was infrequent. CONCLUSIONS: Patients with stronger patch test reactions (++, +++) are more likely to have a clear history of reacting to hair dye and are less likely to still be dyeing their hair.