Relevance Of Patch Test Reactions Research Articles

Frequency and clinical relevance of contact allergy in dental patients.

While many studies have reported on occupational allergic contact dermatitis amongst dental personnel, studies on the relevance of patch testing in dental patients are scarce. To determine the frequency and clinical relevance of contact allergy in patients with intra- and perioral complaints. A total of 360 patients with intra- and perioral complaints suspected of having a contact allergy were patch-tested with the dental allergen series, European Baseline Series, and extended Amsterdam Baseline Series at Amsterdam University Medical Centers between January 2015 and November 2021. A total of 285 patients (79.2%) had a positive patch test reaction for either one (18.6%) or multiple allergens (60.6%). Sodium tetrachloropalladate was the most sensitising allergen with 98 patients (27.2%) testing positive, followed by nickel sulphate (23.3%), methylisothiazolinone (15.6%), and fragrance mix I (14.2%). Clinical relevance was found in 68 of 208 patients (32.7%), with patients having one (15.4%) or multiple (17.3%) patch test reactions clinically relevant to their (peri)oral complaints. Clinically relevant patch test reactions were frequently seen in dental patients. Although this study provides us with a better understanding on the frequency and clinical relevance of contact allergy in dental patients, further studies are needed to confirm our results.

Hand and foot dermatitis in patients referred for patch testing: Analysis of North American Contact Dermatitis Group Data, 2001-2018

Dermatitis localized to hands (HD), feet (FD), or both hands and feet (HFD) has multiple etiologies, including atopic dermatitis, irritant contact dermatitis, and allergic contact dermatitis. Unfortunately, little is known about clinical differences between patients with HD, FD, and HFD. To characterize differences in demographics, etiology, and patch testing results among patients presenting with HD, FD, or HFD referred for patch testing. A retrospective analysis of patients patch tested by the North American Contact Dermatitis Group between 2001 and 2018. Of 43,677 patients who were patch tested, 22.8% had HD, 2.9% had FD, and 3.7% had HFD. Allergic and currently relevant patch test reactions to ≥1 North American Contact Dermatitis Group screening allergen occurred in similar proportions in all 3 study groups. However, HD (18.0%) had higher proportions of occupationally relevant reactions than HFD (8.9%) or FD (4.0%). Nickel and fragrance mix I were in the top 5 currently relevant allergens for HD, FD, and HFD. Other top allergens, as well as allergen sources, differed between HD, FD, and HFD. No data on HD or FD morphology or distribution. HD, FD, and HFD have several differences with respect to patient characteristics, etiologies, and clinically relevant allergens.

Patch testing with cobalt in children and adolescents: North American contact dermatitis group experience, 2001–2018

Allergic contact dermatitis (ACD) to cobalt is more common in children and adolescents than adults. However, detailed information on sites and sources of cobalt ACD is limited. To assess trends in positive and clinically relevant patch test reactions to cobalt in children and associated patient characteristics, common sources and body sites affected. A retrospective analysis of children (<18 years) patch tested to cobalt by the North American Contact Dermatitis Group between 2001 and 2018. Of 1919 children patch tested, 228 (11.9%) and 127 (6.6%) had a positive/allergic or currently relevant patch test reaction to cobalt, respectively. The most common primary body sites affected were scattered generalized (30.0%), face, not otherwise specified (10.6%) and trunk (10.1%). Patients with allergic and currently relevant allergic patch test reactions were more likely to have a primary site of trunk (p=0.0160 and p=0.0008) and ears (p=0.0005 and p < 0.0001). Affected body site(s) varied by cobalt source among patients with currently relevant reactions, especially for less common sources. The most commonly identified sources of cobalt included jewellery, belts and clothing. Positive patch test reactions to cobalt were common in children. The most common body site was scattered generalized and the sources of cobalt varied by body site.

Translated article] Contact Allergy in Patients With Rosacea

Background and objectiveRosacea is a chronic acneiform skin disorder in which impaired skin barrier function can lead to sensitization to allergens. We aimed to analyze contact allergies in our patients with rosacea. Material and methodsRetrospective cohort study of all patients who underwent patch testing in our skin allergy clinic between May 1991 and May 2019. ResultsA total of 200 patients with rosacea were referred to our clinic for patch testing during the study period; they represented 2.1% of all patch tested patients in the period. Eighty-one percent were women (mean age, 44.7years). At least 1 positive patch test was recorded for 46.5%; 15% were of current relevance. The most frequent positive reaction was to nickel (26%), followed by cobalt chloride (6.5%), isothiazolinones (6%), p-phenylenediamine (5.5%), fragrance mix II (5%), and thimerosal (3.5%). The most common currently relevant patch test reactions were to isothiazolinones in 10 of the 200 patients (5%); to phenylenediamine, fragrance mix II, and toluensulfonamide formaldehyde resin in 4 patients (2%) each; and to tixocortol and fragrance mix I in 2 patients (1%) each. The allergen groups most often implicated were metals (of current relevance in 12.6%) and drugs (of current relevance in 25.8%). Preservatives and fragrances were the next most common allergen groups, and 70.8% and 43.7% of the positive reactions in these groups, respectively, were of current relevance. Cosmetics were the most frequent source of sensitization, followed by topical medications—notably corticosteroids and antifungal agents. ConclusionsWe emphasize the high prevalence of allergic contact dermatitis in patients with rosacea, a finding which supports patch testing, especially if eruptions worsen when these patients use cosmetics and topical medications.

Sensibilización alérgica de contacto en pacientes con rosácea

Background and objectiveRosacea is a chronic acneiform skin disorder in which impaired skin barrier function can lead to sensitization to allergens. We aimed to analyze contact allergies in our patients with rosacea. Material and methodsRetrospective cohort study of all patients who underwent patch testing in our skin allergy clinic between May 1991 and May 2019. ResultsA total of 200 patients with rosacea were referred to our clinic for patch testing during the study period; they represented 2.1% of all patch tested patients in the period. Eighty-one percent were women (mean age, 44.7years). At least 1positive patch test was recorded for 46.5%; 15% were of current relevance. The most frequent positive reaction was to nickel (26%), followed by cobalt chloride (6.5%), isothiazolinones (6%), p-phenylenediamine (5.5%), fragrance mixII (5%), and thimerosal (3.5%). The most common currently relevant patch test reactions were to isothiazolinones in 10 of the 200 patients (5%); to phenylenediamine, fragrance mixII, and toluensulfonamide formaldehyde resin in 4 patients (2%) each; and to tixocortol and fragrance mixI in 2 patients (1%) each. The allergen groups most often implicated were metals (of current relevance in 12.6%) and drugs (of current relevance in 25.8%). Preservatives and fragrances were the next most common allergen groups, and 70.8% and 43.7% of the positive reactions in these groups, respectively, were of current relevance. Cosmetics were the most frequent source of sensitization, followed by topical medications — notably corticosteroids and antifungal agents. ConclusionsWe emphasize the high prevalence of allergic contact dermatitis in patients with rosacea, a finding which supports patch testing, especially if eruptions worsen when these patients use cosmetics and topical medications.

Myroxylon pereirae (balsam of Peru): Still worth testing?

BackgroundBecause Myroxylon pereirae (MP), or balsam of Peru, is nowadays almost not used “as such,” and fragrance mix 1 (FM1) apparently is more sensitive in detecting fragrance allergy, the usefulness of testing MP in baseline series was recently questioned.ObjectivesIdentification of the number of clinically relevant patch test reactions to MP not detected by FM1.MethodsRetrospective analysis of 12 030 patients patch tested with MP and FM1 for contact dermatitis between January 2018 and December 2019 in 13 Italian dermatology clinics.ResultsFour hundred thirty‐nine patients (3.6%) had a positive patch test reaction to MP; 437 (3.6%) had a positive patch test reaction to FM1. Positive reactions to both MP and FM1 were observed in 119 subjects (1.0%), 310 (2.6%) reacted to MP only, 304 (2.5%) to FM1 only, 5 to MP and sorbitan sesquioleate (SSO), 9 to FM1 and SSO, and 5 to MP, FM1, and SSO. Single sensitizations were clinically relevant in 75.2% of cases for MP (62.9% current, 12.3% past) and 76.3% for FM1 (70.1% current, 6.2% past).ConclusionsBased on our results, MP appears to be still worth testing along with FM1 in baseline series, because it allows detection of a remarkable number of fragrance allergies, often relevant, which would be otherwise missed.

Patch Testing to Methyldibromoglutaronitrile/Phenoxyethanol: North American Contact Dermatitis Group Experience, 1994-2018.

Methyldibromoglutaronitrile/phenoxyethanol (MDBGN/PE) is a broad-spectrum preservative mixture used in consumer and industrial products. The aims of the study were (1) to characterize the prevalence and clinical relevance of patch test reactions to MDBGN/PE and the epidemiology of positive patients and (2) to determine the frequency of concomitant reactions of MDBGN/PE and its components. This study used a retrospective analysis of cross-sectional data compiled by the North American Contact Dermatitis Group from 1994 to 2018. Of 55,477 tested patients, 2674 (4.8%) had positive patch test reactions to MDBGN/PE (1.0%-2.5% petrolatum [pet]); most were + (63.3%) or ++ (22.3%). Clinical relevance was considered definite in 3.0% and probable in 19.3% of reactions. Common dermatitis sites included the hands (26.4%), scattered/generalized distribution (24.7%), and the face (18.3%). Patients with a positive reaction to MDBGN/PE and/or MDBGN and/or PE were significantly more likely to be male and older than 40 years and/or had hand dermatitis (P ≤ 0.0033). Positivity to MDBGN/PE 2.0% pet decreased significantly over time (from 6.0% in 1998-2000 to 2.5% in 2017-2018, P < 0.0001). Personal care products were the most common exposure source (53.2%). Over time, positivity to MDBGN/PE 2.0% pet decreased significantly from 6.0% (in 1998-2000) to 2.5% (in 2017-2018). The high proportion of weak (63.3%) reactions underscore the need for careful interpretation of patch test sites. Important demographic associations included male sex and age older than 40 years.

Clinical factors before or after device implantation in predicting metal hypersensitivity reactions: A retrospective study.

Metal hypersensitivity reactions (MHR) as a cause of implant-related complications are highly debated and recommendations regarding pre-procedural allergy evaluation vary dramatically. To examine patients referred before or after device implantation and identify factors that could be useful to guide the value of patch testing. Patients who underwent patch testing pre- or post-device implantation between July 2006 and September 2016 were analyzed retrospectively. A series of 127 patients underwent patch testing: pre-implantation (n = 40) and post-implantation (n = 87). In the pre-implant group, a history of metal allergy demonstrated high sensitivity (0.94; 95% CI: 0.83-1.00) and negative likelihood ratio (0.17; 95% CI:0.02-1.29) for diagnosing MHR. No predictive value could be ascribed to any of the clinical symptoms (eg dermatitis, pain, swelling, implant failure, and/or other symptoms) for patients referred following orthopaedic and dental post device implantation. Eight patients in the orthopaedic group and six patients in dental group with relevant patch test reactions underwent implant revisions, and seven and five patients improved, respectively. Pre-implant patch testing for selected individuals with a history of metal allergy can help guide implant choice. Post-implant patch testing may be helpful in some patients if other causes have been excluded, as patients with confirmed MHR benefited from revisions.

Allergic Contact Dermatitis of the Anogenital Region in Men and Women.

Allergic contact dermatitis is an uncommon but important cause of skin disease in the anogenital region. Relevant allergens are described in women and less commonly in men. The aim of this study was to describe outcomes of patch testing in men and women presenting with anogenital dermatoses. Cases patch tested for anogenital conditions at 2 patch test clinics in Sydney, Australia, from 2002 to 2017 were reviewed. Positive and relevant patch test reactions were recorded. Thirty-seven women and 27 men were included. Dermatitis was the most common diagnosis, followed by psoriasis and lichen sclerosus. Thirty percent had a final diagnosis of allergic contact dermatitis. The most frequent relevant allergens were fragrance mix I (9%), patients own products (9%), Myroxylon pereirae (8%), cocamidopropyl betaine (3%), and benzocaine (3%). The top positive and relevant allergens seen were in concordance with other reports from Australia and the rest of the world. Fragrances and medicaments are common allergens, and it is recommended that products used on anogenital skin be fragrance free. Testing patients own products is imperative.

Allergic contact dermatitis in children and proposal for an Australian Paediatric Baseline Series.

Allergic contact dermatitis (ACD) is an increasingly common diagnosis in children. The objectives of this study were to review our experience with ACD in children in tertiary settings, to ascertain the spectrum of allergens in this population and to subsequently propose the first Australian Paediatric Baseline Series for patch testing. We conducted a retrospective analysis of patch test data from 1993 to 2017 from two tertiary referral patch-testing centres in Melbourne, Victoria. A total of 511 children were patch tested during the study period. Of these, 58.3% (298/511) of children tested had a positive patch test, and 65.1% (194/298, or 38.0% of the total) had a relevant positive patch test. The most common relevant patch test reactions were fragrance mix, methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and methylisothiazolinone (MI), Myroxylon pereirae, nickel sulphate, and colophonium. Allergic contact dermatitis is not uncommon in children, and patch testing should be considered in children with suspected ACD or with recalcitrant atopic dermatitis. Based on our experience over 25years, we propose the first Australian Paediatric Baseline Series.

Using Patch Testing to Improve Therapeutic Outcome in the Treatment of Hand Eczema in Vietnamese Patients.

BACKGROUND:Hand eczema is a common chronic and relapsing skin disease with various clinical features. Hand eczema aetiology can be allergic contact dermatitis (ACD), irritant contact dermatitis (ICD), atopic dermatitis (AD) and unknown or combination causes. If the causative agents are not detected treatment of hand eczema will be a failure. A patch test can be useful to detect causative agents in suspected allergic contact hand eczema. Then patients will avoid contacting them. This results in the improvement of hand eczema. In Vietnam, patch test has not been used before, so we conduct this study.AIM:To identify causative allergens by using patch test with 28 standard allergens in consecutive patients.METHODS:A group of 300 HE patients from the National Hospital of Dermatology and Venereology (NHDV) in Vietnam were enrolled in this study. They were divided into 4 groups-ACD, ICD, AD and unknown aetiology. The patient was patch tested with 28 standard allergens to identify the causative agents.RESULTS:Among the 300 HE enrolled patients, ACD accounted for 72.7%, AD and ICD had the same rate of 12.7%. 39.3% of the patients had a positive patch test. Reaction to nickel sulfate was the most common (10.3%), followed by potassium dichromate (9.7%), cobalt (4%) and fragrance mix (3.1%). About one-third of the cases had relevant clinical reactions correlated with the contact agents and clinical history. Males reacted to cement, thiuram mix and formaldehyde more than females, while females reacted to a nickel more than males.CONCLUSIONS:Hand eczema has variable clinical features and diverse aetiology. ACD is an important cause of hand eczema that can be managed with a patch test to detect causative allergens. Nearly 40% of HE cases had positive patch test. Relevant patch test reactions were seen in one-third of the patients. We propose using patch test detect causative agents in suspected allergic contact hand eczema. Then patients will avoid contacting them. This results in the improvement of hand eczema.

Pilot study on a new concept of documenting the clinical relevance of patch test results in contact dermatitis patients

Assessment of the clinical relevance of patch test reactions is an essential part of the diagnostic work-up of patients with (occupational) contact dermatitis. However, final diagnostic information, particularly the clinical relevance of allergic patch test reactions, has hitherto been ill-represented in clinical documentation systems (patch test software) and surveillance registries based on these. To develop, implement as a pilot study, and analyse concerning feasibility and contents a new concept of representing the full scope of diagnostic information utilized in the diagnosis of patients with (occupational) contact dermatitis. On the basis of a European working group discussion on items to document and catalogue lists to use for this purpose, an online documentation system to collect data was set up, followed by pilot use involving 9 dermatology departments across Europe. Data on 176 patients with suspected occupational hand dermatitis were included; among these, work-relatedness was confirmed in 150, and in 53 non-occupational aetiology was the sole or a contributory cause. Data were further analysed with regard to occupations, product categories, substances (haptens), source of information on which the evaluation was based, and various combinations of these factors, to illustrate the usefulness of the proposed data representation. An improved method of data collection is presented that more accurately links allergen to exposure and to clinical disease and patient history, and thus better represents clinical relevance. This enables more precise analysis of the causation of contact dermatitis, occupational or non-occupational, and thereby better targeting of prevention. The development of future databases should incorporate the above considerations to record the results of investigation.

Allergic contact dermatitis in children: which factors are relevant? (review of the literature)

Allergic contact dermatitis (ACD) in children is increasing. Sensitization to contact allergens can start in early infancy. The epidermal barrier is crucial for the development of sensitization and elicitation of ACD. Factors that may influence the onset of sensitization in children are atopic dermatitis, skin barrier defects and intense or repetitive contact with allergens. Topical treatment of ACD is associated with cutaneous sensitization, although the prevalence is not high. ACD because of haptens in shoes or shin guards should be considered in cases of persistent foot eruptions or sharply defined dermatitis on the lower legs. Clinical polymorphism of contact dermatitis to clothing may cause difficulties in diagnosing textile dermatitis. Toys are another potentially source of hapten exposure in children, especially from toy-cosmetic products such as perfumes, lipstick and eye shadow. The most frequent contact allergens in children are metals, fragrances, preservatives, neomycin, rubber chemicals and more recently also colourings. It is very important to remember that ACD in young children is not rare, and should always be considered when children with recalcitrant eczema are encountered. Children should be patch-tested with a selection of allergens having the highest proportion of positive, relevant patch test reactions. The allergen exposure pattern differs between age groups and adolescents may also be exposed to occupational allergens. The purpose of this review is to alert the paediatrician and dermatologist of the frequency of ACD in young children and of the importance of performing patch tests in every case of chronic recurrent or therapy-resistant eczema in children.

Contact allergy and allergic contact dermatitis in children - a review of current data

Allergic contact dermatitis (ACD) in children was previously considered to be a rare occurrence. However, the growing number of case reports and cross-sectional studies through the past three decades indicate that ACD is, in fact, a highly relevant diagnosis in children. Furthermore, the frequency of ACD in children seems to be increasing. In 1999, a review of the literature reported prevalence rates of 14.5-70% in selected paediatric populations. The current paper reviews the studies on the prevalence of positive patch test reactions and ACD in the paediatric population during the past decade, and provides an overview of the main findings. We found reported sensitization rates of 26.6-95.6% in selected groups of children. The associated relevance was 51.7-100%. The most common allergens were nickel, cobalt, thimerosal, and fragrance. Tailored patch testing increases the rate of relevant patch test reactions. Children with atopic dermatitis are as frequently sensitized as children with no history of atopic dermatitis, and there are no differences associated with sex. Children and adults can be tested with equal concentrations of patch test allergens. Our findings may support the notion that the prevalence of ACD in children is increasing over time or indicate an increased awareness.

Positive patch test reactions in older individuals: Retrospective analysis from the North American Contact Dermatitis Group, 1994-2008

Relatively little is known about the epidemiology of allergic contact dermatitis in older individuals. We sought to determine the frequency of positive and clinically relevant patch test reactions in older individuals (≥ 65 years old) referred for patch testing, and to compare these results with those of adults (≤ 64-19 years) and children (<18 years). This was a retrospective cross-sectional analysis of North American Contact Dermatitis Group data from 1994 to 2008. A total of 31,942 patients (older n = 5306; adults n = 25,028; children n = 1608) were patch tested. The overall frequency of at least one allergic reaction in older individuals was 67.3% as compared with 66.9% for adults (P = .5938) and 47% for children (P = .0011). Reaction rates that were statistically higher in older individuals as compared with both adults and children included: Myroxylon pereirae, fragrance mix I, quaternium-15, formaldehyde, imidazolidinyl urea, diazolidinyl urea, neomycin, bacitracin, methyldibromo glutaronitrile, methyldibromo glutaronitrile/phenoxyethanol, ethyleneurea melamine formaldehyde mix, and carba mix (P values < .0004). Patch test reaction rates that were significantly lower in older individuals than both comparison groups included: nickel, thimerosal, and cobalt (P values < .0001). Referral population was a limitation. Older individuals were more likely to have at least one positive patch test reaction as compared with children, but had similar rates to adults. The frequency of positive reactions to specific allergens differed by age group, most likely as a result of exposures.

Formaldehyde‐releasers: relationship to formaldehyde contact allergy. Formaldehyde‐releasers in clothes: durable press chemical finishes. Part 1

This is one of a series of review articles on formaldehyde-releasers and their relationship to formaldehyde contact allergy and in this paper formaldehyde-releasers used as durable press chemical finishes (DPCF) in textiles are discussed. The literature on allergy to DPCF since 1980 is presented in two parts. Part 1 (this article) presents a short historical overview of the problems with formaldehyde in clothes and discusses the chemistry of durable press chemical finishes, legislation in various countries, and studies on the amount of formaldehyde present in clothes. In addition, the DPCF that have caused contact allergy are presented with CAS, synonyms, molecular formula, chemical structure, applications, and patch test studies. In the forthcoming part 2, the frequency of sensitization to DPCF, occupational contact sensitization, relevance of patch test reactions, and relationship to formaldehyde contact allergy will be reviewed, followed by a discussion of both parts of the article together.

Patch-Testing While on Systemic Immunosuppressants

Occasionally, the need arises to patch-test patients while they are on immunomodulators. Little is known about how these systemic agents affect the results of patch testing. To present data on 11 patients who underwent patch testing while under the effects of immunosuppressants. Retrospective chart reviews were performed on 11 patients who underwent patch testing while they were taking various systemic immunosuppressants or within 48 hours of cessation of various systemic immunosuppressants. Patients had been taking prednisone (n = 6), cyclosporine (n = 2), combination cyclosporine and prednisone (n = 1), mycophenolate mofetil (n = 1), and infliximab (n = 1) up to 48 hours prior to and/or during patch testing. Seven patients showed at least one strong (++) or extreme (+++) patch-test reaction. Three patients had at least one weak (+) reaction. One patient showed only questionable reactions. The patient on mycophenolate was eventually retested while off immunosuppressants and showed strong clinically relevant patch-test reactions. Overall, 8 of the 11 patients reported some improvement in their dermatitis, including all the patients with strong or extreme reactions. While it is optimal for patch testing to be performed when patients are off immunosuppressants, immunosuppressive therapies should not be an absolute contraindication to patch testing.

Formaldehyde‐releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde‐releasers

This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed in the literature as formaldehyde-releasers, data are inadequate to consider them as such beyond doubt. Several (nomenclature) mistakes and outdated information are discussed. Formaldehyde and formaldehyde allergy are reviewed: applications, exposure scenarios, legislation, patch testing problems, frequency of sensitization, relevance of positive patch test reactions, clinical pattern of allergic contact dermatitis from formaldehyde, prognosis, threshold for elicitation of allergic contact dermatitis, analytical tests to determine formaldehyde in products and frequency of exposure to formaldehyde and releasers. The frequency of contact allergy to formaldehyde is consistently higher in the USA (8-9%) than in Europe (2-3%). Patch testing with formaldehyde is problematic; the currently used 1% solution may result in both false-positive and false-negative (up to 40%) reactions. Determining the relevance of patch test reactions is often challenging. What concentration of formaldehyde is safe for sensitive patients remains unknown. Levels of 200-300 p.p.m. free formaldehyde in cosmetic products have been shown to induce dermatitis from short-term use on normal skin.

Thimerosal and the Relevance of Patch-Test Reactions in Children

Thimerosal (C(9)H(9)HgNaO(2)S) is a mercuric derivative of thiosalicylic acid that goes by many names. It has been used as a disinfectant (eg, Merthiolate) and as a preservative in some vaccines, cosmetics, tattoo inks, eye drops, and contact lens solutions. It remains one of the least likely chemicals to cause contact allergy and for this reason has been removed from many standard screening series. Positive patch-test reactions (demonstrating sensitization) may still be seen (especially in older children); however, these reactions are not clinically relevant and are expected to be fewer, reflecting changes in current vaccine formulations.

Clinically Relevant Patch Test Reactions in Children—A United States Based Study

Allergic contact dermatitis in the pediatric population is more common than previously recognized, with recent prevalence estimates of positive patch test reactions in the range of 14-70% of children patch tested. The aim of this study was to confirm the prevalence of clinically relevant allergic contact dermatitis in children at two referral centers and determine the most common contact allergens. We performed a retrospective case series analysis of 65 symptomatic children (35 girls and 30 boys) aged 1-18 years old who were patch tested over a 5-year period for recalcitrant dermatitis. Positive patch test reactions were noted in 54 of the 65 children (prevalence rate of 83%) to 80 different allergens. Fifty children (77%) had positive reactions which were determined to be of "definite" or "probable" current clinical relevance. We conclude that the diagnosis of allergic contact dermatitis to specific relevant allergens is common in children referred for patch testing and that contact allergy should be considered in all children with recalcitrant dermatitis. With this article, we review the literature and present a US based study regarding the clinical relevance of positive patch test reactions in children.