The Characteristics of Allergic Contact Dermatitis in Military and Civilian Populations: A Multicenter Cross-Sectional Study.

Background: Contact dermatitis is a common condition in the general population, with a global prevalence of 20%. It is an inflammatory skin disease that is classified as irritant contact dermatitis (80%) and allergic contact dermatitis (ACD) (20%). In addition, it is the most common presentation of occupational dermatoses and is one of the primary reasons for seeking medical attention among military personnel. Only few studies have compared the characteristics of contact dermatitis in soldiers and civilians. Objective: To compare the characteristics of ACD between civilians and soldiers. Methods: This large retrospective study was conducted in Israel and involved 1800 civilians and 750 soldiers with suspected ACD. All patients underwent relevant patch tests based on their clinical presentation and medical history. Results: At least 1 positive allergic reaction was found in 382 civilians (21.22%) and 208 soldiers (27.73%) (nonsignificant). Moreover, 69 civilians (18.06%) and 61 soldiers (29.32%) had at least 1 positive occupational allergic reaction (P < 0.05). Widespread dermatitis was significantly more common among soldiers. The most frequent occupations among civilians with positive allergic reactions were hairdressers/beauticians. "Professional, technical, and managerial occupations" were the most frequent categories among soldiers (24.6%), with computing professionals being the most common occupation (46.67%). Conclusion: Military personnel and civilians have different characteristics associated with ACD. Therefore, considering these characteristics before placement in a workplace can help prevent ACD.

Hazard identification and the prevalence of occupational skin disease in Indonesian Batik workers.

Batik, a resist-dyeing technique to decorate a special cotton fabric, has been practiced for centuries in Indonesia. Unfortunately, as an informal enterprise, batik industry activities lack work safety and health regulations. This study aimed to identify potential health hazards, including inventorying the chemicals to which the workers are exposed, the PPE profile, and investigating the prevalence of occupational skin diseases (OSD) in the batik industry. A cross-sectional study and an inventory of exposure to the chemicals were done in traditional batik workplaces in 5 districts in Yogyakarta province, Indonesia. The chemicals were classified as potential sensitizers/irritants, and the workers were examined and interviewed using the Nordic Occupational Skin Questionnaire-2002/LONG. Of 222 traditional batik workers, OSD were diagnosed in 61 (27.5%) workers, with occupational contact dermatitis was the most common OSD encountered (n = 23/61; 37.7%) (allergic contact dermatitis n = 7/23; irritant contact dermatitis n = 16/23). A smaller portion of other OSD was also encountered including callus, miliaria, and nail disorder (9%, 6.3%, and 5.9%, respectively). During each step of the traditional batik manufacturing process, the workers are exposed to substances that act as irritants and/or as potential contact allergens. However, only one-fourth of the workers used PPE regularly, particularly during the coloring process and wax removal (wet processes). Traditional batik manufacturing process exposes the worker to various physical and chemical hazards, resulting in a high prevalence of occupational skin diseases, especially contact dermatitis among the employees.

Patch tests and hand eczema: retrospective study in 173 patients and literature review.

BACKGROUND: Hand eczema (HE) is a highly prevalent, recurrent, and multifactorial disease. It encompasses a group of eczematous diseases that affect the hands, etiologically classified into irritant contact dermatitis (ICD), allergic contact dermatitis (ACD) and atopic dermatitis (AD). Few epidemiological studies in Latin America have investigated the characteristics of patients with this condition and the origin of the disease. OBJECTIVES: To analyze the profile of patients diagnosed with HE submitted to patch tests aiming to determine its etiology. METHODS: A retrospective descriptive study was carried out on epidemiological data and patch tests of patients with HE treated at a tertiary hospital in the city of São Paulo from January 2013 to December 2020. RESULTS: A total of 173 patients were studied, whose final diagnosis was 61.8% of ICD, 23.1% of ACD and 5.2% of AD, with diagnostic overlap in 42.8% of the cases. The main positive and relevant patch tests were: Kathon CG (42%), nickel sulfate (33%), and thiuram mix (18%). STUDY LIMITATIONS: The number of treated cases and socioeconomic profile was limited to a vulnerable population group. CONCLUSION: HE is a diagnosis in which overlapping etiologies are frequent, with the main sensitizers identified in ACD being Kathon CG, nickel sulfate and thiuram mix.

Occupational Skin Dermatitis among Healthcare Workers Associated with the COVID-19 Pandemic: A Review of the Literature.

The skin is the outermost layer of the human body and is continually exposed to numerous external stimuli, which can cause unwanted skin irritation. Occupational skin diseases are the most prevalent form of work-related illness and are found in a variety of sectors, particularly healthcare. During the recent COVID-19 pandemic, healthcare professionals experienced a variety of unexpected, unusual occupational skin diseases associated with COVID-19-engaged employment. Because the clinical characteristics of these types of skin inflammation are unique, this review focuses on the characteristics of a large category of occupational workers, namely COVID-19-engaged healthcare professionals. Furthermore, we examined the potential pathogeneses of occupational skin disorders associated with COVID-19-engaged labor, as well as different preventative methods.

Work-related and personal risk factors for occupational contact dermatitis: A systematic review of the literature with meta-analysis.

The objective of this review is to identify work-related and personal risk factors for contact dermatitis (CD), and assess their association with this frequently occurring occupational disease. A systematic review of the literature from 1990 to June 2, 2020, was conducted using Medline and Embase. Prospective cohort and case-control studies were included, and meta-analyses were conducted when feasible. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation. Twenty-nine studies were identified, comprising 26 study populations and with a total of 846 209 participants investigating 52 risk factors for CD. Meta-analyses were performed for five risk factors, all of them for irritant contact dermatitis (ICD). Moderate-quality evidence was found for associations between wet work and ICD (OR: 1.56, 95%CI: 1.21-2.01). High-quality evidence was found for the association between atopic dermatitis and ICD (OR: 2.44, 95%CI: 1.89-3.15). There was no evidence for an association between ICD and sex or history of hand dermatitis, respiratory and mucosal atopy. In conclusion, several work-related and personal risk factors associated with CD were identified. Our data emphasize the need for the assessment of both, work-related and personal, risk factors to prevent occupational CD.

Improving Recovery of Irritant Hand Dermatitis in Healthcare Workers With Workplace Interventions During the COVID-19 Pandemic.

Introduction: Occupational hand dermatitis is common among healthcare workers, with increased incidence during the COVID-19 pandemic. Irritant contact dermatitis accounts for the majority of occupational hand dermatitis and is largely due to frequent contact with hand hygiene products. Long-term prognosis of occupational contact dermatitis is often very poor. This study aims to identify and implement suitable workplace interventions to aid in the recovery of occupational irritant hand dermatitis among healthcare workers during the COVID-19 pandemic. Methods: A quality improvement (QI) project was performed in a tertiary hospital using the Plan-Do-Study-Act model. Healthcare workers seen at the Occupational Dermatology Clinic from March 2020 to May 2021 for the first time for likely occupational irritant dermatitis were targeted for the project. Four workplace interventions were implemented: (a) substitute current alcohol-based hand rub (ABHR) with a different, gentler ABHR, (b) alternate ABHR with gentle hand wash products, (c) temporary job modification with less clinical work (d) switch latex gloves to nitrile gloves. The improvement was assessed after 2 months of workplace intervention using a visual analogue scale, based on changes seen on photographs taken at the baseline and monthly review. The target improvement was set at 70% after 2 months of workplace interventions. Results: A total of 21 participants were included in the QI project. All participants were found to have significant improvement in their hand condition. The estimated mean reduction of signs and symptoms was 80% in comparison to their baseline hand condition before intervention. Conclusion: Workplace interventions such as substituting irritant hand hygiene products with gentler alternatives and temporary reduction in clinical duties may be useful in improving the recovery rate of irritant hand dermatitis among healthcare workers. Areas with high hand hygiene workload or high incidences of hand dermatitis may opt to implement systemic workplace changes.

Skin symptoms in veterinary assistant staff and veterinarians: A cross-sectional study.

BACKGROUND: Veterinary assistants and veterinarians are at an increased risk of developing an occupational skin disease, for example, irritant/allergic contact dermatitis, contact urticaria and hand eczema (HE). OBJECTIVES: We aimed to investigate the prevalence of skin problems and the influence of predisposing factors especially among veterinary assistants. METHODS: We conducted a cross-sectional study among veterinary assistant staff (n = 103) and veterinarians (n = 19). A questionnaire, specific IgE determination and photographs of hands were evaluated for skin symptoms. Logistic regression models assessed predisposing factors. RESULTS: Over 50% (n = 62/122) of our study population reported hand eczema (HE) in the last 12 months (1-year prevalence). Twenty-seven subjects reported redness and contact urticaria directly after animal contact, 35 had a positive history of allergic contact dermatitis. HE was associated with (i) increased frequency of hand washing (11-15 times per day; OR 4.15, confidence interval [CI] 95% 1.18-14.6, p = 0.027, univariate model) and (ii) unprotected contact to fluids and tensides >5 times per day (OR 4.56, CI 95% 1.53-13.6, multivariate model). CONCLUSIONS: We observed a high prevalence of self-reported HE among staff in veterinary practices. Excessive hand washing, unprotected contact with irritants and long-term glove use should be avoided.

SKIN FEATURES IMPORTANT FOR THE OCCURRENCE OF CONTACT DERMATITIS IN HEALTHCARE WORKERS.

The occurrence of skin lesions in healthcare workers is associated with a negative impact on important skin functions, including protection from mechanical injuries, sunlight, dehydration, and penetration of chemical substances or pathogenic microorganisms. In healthcare professionals, the most common occupational skin disease is contact dermatitis (CD), either irritant (ICD) or allergic (ACD), and typically on the hands. ICD accounts for about 80% of occupational CD, making it the most frequent cause. According to the literature, CD frequency is higher among healthcare professionals than other occupations, with critical occupational risk factors including contact with irritants and allergens at the workplace. Furthermore, ICD is a multifactorial disorder influenced by many constituent and environmental factors. Constituent factors include age, gender, body location, atopy, and genetic factors, while environmental factors include temperature, airflow, humidity, and occlusion. Commonly encountered irritants are water, detergents and surfactants, solvents, oxidizing agents, acids, and alkalis; however, use of protective gloves or equipment, hand-washing habits, use of cleansers and creams, active inflammatory skin diseases, and daily activities are also important for ICD onset. Additionally, ICD is known to predispose to ACD. Important risk factors for ACD development include occupation, age, history of atopic dermatitis, genetics, female gender, and fair skin phototype. In summary, numerous skin features and other occupation-related factors contribute to CD among healthcare practitioners. Given the high level of exposure to contact irritants/allergens in the healthcare setting, implementation of preventive measures is crucial for a safer work environment.

Occupational contact dermatitis: Retrospective analysis of North American Contact Dermatitis Group Data, 2001 to 2016.

BACKGROUND: Patch testing is an important diagnostic tool for suspected allergic contact dermatitis (ACD) in occupational settings. OBJECTIVE: Provide an overview of occupational skin disease (OSD) and an analysis of occupational ACD in North American patients undergoing patch testing between 2001and 2016. METHODS: Patients with OSD were analyzed for frequency of allergic reactions to a screening series of allergens, occupational relevance, location of skin disease, and exposure sources. Demographic, occupation, and industry information were recorded. RESULTS: Of 38,614 patients evaluated, 4471 (11.6%) had OSD, of whom 3150 (70.5%) had ACD. The most common occupationally related allergens included rubber accelerators, preservatives, and bisphenol A epoxy resin. Hands (75.8%), arms (30.0%), and face (15.9%) were common sites of dermatitis. The occupations most affected were service workers and machine operators. LIMITATIONS: Our cohort may not reflect the general working population. CONCLUSION: This study identified common occupational allergens, exposure sources, and occupations/industries at risk. This information may help the clinician evaluate and manage patients with occupational contact dermatitis.

Occupational contact allergy of construction workers in Greece: Trends during 2009-2018.

BACKGROUND: Recent trends in the sensitization of construction workers show a decrease in potassium dichromate and an increase in epoxy resin sensitization. OBJECTIVES: To present the trends of occupational contact allergy of construction workers in Greece from 2009 to 2018. METHODS: We retrospectively reviewed the files of patients with eczema patch tested in our Contact Dermatitis Clinic who were construction workers. RESULTS: A total of 191 construction workers initially reported contact dermatitis. Of these, 138 had occupation-relevant allergic contact dermatitis (ACD) or irritant contact dermatitis (ICD). All patients were men. After being patch tested, 98 (71.0%) were diagnosed with ACD and 40 with ICD. Median duration of occupation till onset of ACD was 2 years (interquartile range [IQR] 0.8-7). The hands were the most common location for ACD (73.5%), followed by the trunk (39.8%), the legs (38.8%), and the face (11.2%). Of the patients, 74.6% had lesions affecting multiple body sites. Potassium dichromate (67%) was the most frequent allergen, followed by thiuram mix (37.4%) and cobalt chloride (31.8%). Sensitization to epoxy resins was lower (12.1%). CONCLUSION: The sensitization pattern of Greek construction workers does not follow the trends in Central or Northern Europe, rather sharing attributes with less industrialized countries.

Increased prevalence of irritant hand eczema in health care workers in a dermatological clinic due to increased hygiene measures during the SARS-CoV-2 pandemic.

BACKGROUND: Hand hygiene measures in the general population and in health care workers have increased considerably since the outbreak of the COVID-19 pandemic. OBJECTIVES: To investigate the prevalence and symptoms of hand eczema, as well as hygiene measures and concepts of care, in German health care workers. MATERIALS & METHODS: This was an observational questionnaire study to investigate hygiene and skin care habits, as well as the prevalence and symptoms of hand eczema in 66 nurses and doctors of our dermatology department before and during the SARS-CoV-2 pandemic. RESULTS: Hand washing and hand disinfection procedures increased significantly during the COVID-19 pandemic. Self-diagnosed hand eczema was reported by 33% of the participants, with a median duration of 14 days. The majority of staff currently affected by hand eczema were free of eczema a month previously (82%) and would treat their skin condition with emollients (77%). Erythema, scaling, burning and fissures were reported by 66.1% of the participants and were classified as predominant signs of toxic-irritant hand dermatitis rather than contact allergy. CONCLUSION: Overall, the SARS-CoV-2 pandemic has led to a significant increase in the incidence of signs of irritant hand eczema despite intensified emollient use as a preventive measure. Awareness of the prevalence of hand eczema in health care workers in Germany during the COVID-19 pandemic should be raised, and preventive measures should be intensified.

Incidence rates of occupational contact dermatitis in Denmark between 2007 and 2018: A population-based study.

BACKGROUND: Recent population-based studies on the incidence rates (IRs) of occupational contact dermatitis (OCD) are sparse. OBJECTIVES: To determine the IRs of OCD and development thereof between 2007 and 2018 in known risk occupations. METHODS: Data on all recognized cases of OCD were used to calculate IRs as the number of recognized OCD cases per 10 000 workers per year. Asymptotic chi-square test was used to compare the IRs between 2007-2012 and 2013-2018. RESULTS: The median age at notification of OCD was below 30 years for several of the examined occupations. Hairdressers and beauticians, bakers, dentists and dental assistants, and manufacturing of windmills had the highest overall IRs of OCD. We found a statistically significant increase in the IRs of OCD for child/nursery care workers. CONCLUSIONS: The median age at notification of OCD was low for several of the occupations, signifying the need for further preventive strategies among young people. Based on the IRs of OCD, future preventive efforts should be directed at hairdressers and beauticians, bakers, dentists and dental assistants, and manufacturing of windmills. Furthermore, the statistically significant increase in IRs of OCD among child/nursery care workers highlights the need for further preventive strategies in this field.

Contact dermatitis.

Contact dermatitis (CD) is among the most common inflammatory dermatological conditions and includes allergic CD, photoallergic CD, irritant CD, photoirritant CD (also called phototoxic CD) and protein CD. Occupational CD can be of any type and is the most prevalent occupational skin disease. Each CD type is characterized by different immunological mechanisms and/or requisite exposures. Clinical manifestations of CD vary widely and multiple subtypes may occur simultaneously. The diagnosis relies on clinical presentation, thorough exposure assessment and evaluation with techniques such as patch testing and skin-prick testing. Management is based on patient education, avoidance strategies of specific substances, and topical treatments; in severe or recalcitrant cases, which can negatively affect the quality of life of patients, systemic medications may be needed.

Allergic contact versus irritant contact dermatitis in patients with hard-to-heal leg ulcer: clinical and diagnostic approach.

BACKGROUND: Dermatitis of surrounding skin may complicate hard-to-heal leg ulcers, delaying wound healing. The coexistence of hard-to-heal leg ulcers and irritant or allergic contact dermatitis may create difficulties for both diagnostic and therapeutic management. OBJECTIVE: The aim of our study was to evaluate the incidence of dermatitis occurring in the surrounding skin in a population affected by hard-to-heal leg ulcers during treatment, and to differentiate between allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD) with the use of a patch test. Furthermore, we investigated which medications were most probably related to these conditions. METHOD: We conducted an observational study from 21 February to 21 July 2017, enlisting all patients affected by hard-to-heal leg ulcers who attended the Wound Care Service of the Dermatologic Department of ASST, Spedali Civili, Brescia, Italy. RESULTS: We enrolled 95 patients; 81 patients did not develop dermatitis, while 14 patients developed dermatitis of the surrounding skin. These patients underwent a patch test which gave a positive result in seven patients, permitting the diagnosis of ACD. CONCLUSION: Our study confirmed the incidence of dermatitis of the surrounding skin reported in the literature but reassessed the incidence of ACD as opposed to ICD.

Paederus Dermatitis Outbreak in Addis Ababa, Ethiopia: A Case-Control Study.

Background: Paederus dermatitis is an irritant contact dermatitis caused by crushing insects of the genus Paederus, which releases a vesicant toxin called pederin. On July 28, 2018, the district health office received a report of cases with erythema, itching, and burning after contact with the Paederus insect. In response, we investigated the outbreak intending to describe, confirm, and identify the risk factors associated with the country's first reported outbreak. Methods: A community-based unmatched case-control study was conducted from August 10 to 22, 2018. Two hundred twenty-five (75 cases and 150 controls) study participants were involved in the study. Cases were defined as Bole subcity residents who had acute contact dermatitis after contact with the insect, while controls were persons who did not have contact with the insect. Cases were recruited consecutively as they present, whereas controls were selected by the neighborhood sampling method. An interviewer-administered questionnaire was used for the data collection, and multiple logistic regression was applied to determine the independent risk factors. The results were expressed as adjusted odds ratios (AORs) and 95% confidence intervals (CIs). Results: A total of 122 cases were reported from the three districts of the subcity. The mean age of cases and controls was 23.6 (SD ± 16.4) and 29.4 (SD ± 10.9) years, respectively. Multivariate analysis showed that the presence of outdoor light (AOR = 5.1; 95% CI (2.5, 10.9), presence of rotten leaves (AOR = 6.4; 95% CI (2.9, 15.7)), sleeping on the floor (AOR = 6.1; 95% CI (2.5, 15.7)), wearing protective clothing (AOR = 0.2; 95% CI (0.1, 0.4)), and use of insect repellant (AOR = 0.1; 95% CI (0.0, 0.4)) were significantly associated with Paederus dermatitis outbreak. Conclusion: The investigation identified exposure to artificial light and the presence of rotten leaves around the residential area as important factors leading to an increase in the odds of Paederus dermatitis. In contrast, the use of insect repellant and wearing protective clothing were shown to provide protection. The investigation determined that reducing burning outdoor lights, cleaning excess vegetation, avoiding sleeping on the floor, using insect repellants, and wearing protective clothing can reduce the risk of contracting Paederus dermatitis.

Hand Dermatitis in the Time of COVID-19: A Review of Occupational Irritant Contact Dermatitis.

Occupational contact dermatitis accounts for 95% of all cases of occupational skin disease with irritant contact dermatitis (ICD) constituting 80% to 90% of these cases. Health care workers, hairdressers, and food service workers are typically most affected by occupational ICD of the hands as these occupations require frequent hand hygiene and/or prolonged exposure to water, also known as "wet work." In the context of the current COVID-19 pandemic, frequent hand hygiene has become a global recommendation for all individuals, and new workplace guidelines for hand sanitization and surface sterilization are affecting occupations not previously considered at risk of excessive wet work including grocery or retail workers, postal workers, sanitization workers, and others. In this review, we discuss the etiology and pathogenesis of occupational ICD with additional focus on treatment and interventions that can be made at an institutional and even national level for education and prevention of ICD resulting from frequent hand hygiene.

Clinical manifestations and progression, seasonal variation, and environmental factors associated with Paederus dermatitis among patients attending the outpatient dermatology clinic of Thailand's largest national tertiary referral center: a prospective cohort study.

INTRODUCTION: Paederus dermatitis (PD) is a skin reaction to a chemical substance called paederin, which emanates from a beetle of Paederus spp. This study's objective was to investigate the clinical manifestations and progression, seasonal variation, and environmental factors associated with PD among patients attending the outpatient dermatology clinic of Siriraj Hospital. METHODS: This prospective cohort study included patients who were diagnosed with PD at the Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand during the October 2017 to July 2018 study period. Sociodemographic and environmental data were collected by questionnaire. RESULTS: Twenty-five PD patients (16 females, 9 males) were included with a mean age of 40.9 years (range 17-69 years). The most common sites were the upper and lower extremities. Erythema, linear, and kissing lesions (where two skin surfaces contact) were found in 100%, 32%, and 28% of patients, respectively. Seventy-six percent of patients demonstrated more than one lesion. Eighty percent of patients lived in Bangkok, and 44% of patients had a home near a farm or forest. Fluorescent lighting was used in the homes of 24 patients. All 25 patients were treated with topical steroid, and some received other supportive regimens. Two patients had post-inflammatory hyperpigmentation as a complication; only 7 of 25 patients attended the scheduled follow-up visit. CONCLUSION: In Thailand, PD presents throughout the year, but the most active month is December. Skin lesions vary from mild irritant dermatitis to severe dermatitis, and the average time to complete cure is 12 days. History and clinical manifestation are essential for accurate diagnosis.

Hairdressers' occupational skin diseases in the Finnish Register of Occupational Diseases in a period of 14 years.

BACKGROUND: Hairdressers have a high risk of occupational contact dermatitis caused by exposure to wet work and allergens in hairdressing chemicals. OBJECTIVES: To examine the distribution of diagnoses of occupational skin diseases (OSDs) and their main causes in hairdressers based on a national register data on occupational diseases. METHODS: We retrieved cases of recognized OSDs in hairdressers from the Finnish Register of Occupational Diseases (FROD) in years 2005-2018. RESULTS: During the 14-year period, a total of 290 cases of recognized OSD in hairdressers were registered in the FROD. Allergic contact dermatitis (ACD) was diagnosed in 54%, irritant contact dermatitis in 44%, and contact urticaria (CU) in 5% of them. ACD was most commonly caused by hair dye products and their ingredients (N = 57), persulfates (N = 35), and preservatives (N = 35; mainly isothiazolinones). Acrylates emerged as hairdressers' occupational contact allergens (N = 8) probably due to introduction of structure nails into hair salons. Persulfates was the most common cause of CU. CONCLUSIONS: ACD was the most common OSD in hairdressers. Our analysis confirms that preservatives are important causes of ACD in hairdressers in addition to hair dye products and persulfates. Acrylates emerged as hairdressers' occupational contact allergens, but contact allergy to perming agents remained rare.

Hand dermatitis in adults referred for patch testing: Analysis of North American Contact Dermatitis Group Data, 2000 to 2016.

BACKGROUND: Hand eczema (HE) is a heterogeneous and burdensome disorder. OBJECTIVE: To characterize the clinical characteristics, etiologies and allergen relevance in adults with HE referred for patch testing. METHODS: Retrospective analysis (2000-2016) of North American Contact Dermatitis Group data (n = 37,113). RESULTS: Overall, 10,034 patients had HE, with differences of overlap between allergic contact, irritant contact, and atopic dermatitis. Allergic contact HE fluctuated, whereas atopic HE steadily increased, and irritant HE decreased over time. HE was associated with higher proportions of positive patch tests (67.5% vs 63.8%; χ2, P < .0001). The five most common clinically relevant allergens were methylisothiazolinone, nickel, formaldehyde, quaternium-15, and fragrance mix I. HE was associated with significantly higher odds of positive patch test reactions and clinical relevance in 13 and 16 of the 25 most common allergens, respectively, including preservatives, metals, topical medications, and rubber accelerators. LIMITATIONS: No data on HE phenotype. CONCLUSION: HE in adults was associated with higher proportions of positive patch tests, with a heterogeneous profile of allergens. Patch testing remains an important tool in the evaluation of patients with HE.

Scalp involvement in patients referred for patch testing: Retrospective cross-sectional analysis of North American Contact Dermatitis Group data, 1996 to 2016.

BACKGROUND: Scalp conditions are often multifactorial. OBJECTIVE: To characterize patients with scalp involvement and patch-testing outcomes. METHODS: Retrospective cross-sectional analysis of North American Contact Dermatitis Group data (1996-2016). Study groups included patients with scalp involvement (≤3 anatomic sites coded) with or without additional sites. RESULTS: A total of 4.8% of patients (2331/48,753) had scalp identified as 1 of up to 3 affected anatomic sites. Approximately one-third of "scalp-only" individuals had a specific primary diagnosis of allergic contact dermatitis (38.6%), followed by seborrheic dermatitis (17.2%) and irritant contact dermatitis (9.3%). When adjacent anatomic sites were affected, allergic contact dermatitis was more frequently identified as the primary diagnosis (>50%). The top 5 currently clinically relevant allergens in scalp-only patients were p-phenylenediamine, fragrance mix I, nickel sulfate, balsam of Peru, and cinnamic aldehyde. Methylisothiazolinone sensitivity was notable when adjacent anatomic sites were involved. The top 3 specifically identified sources for scalp-only allergens were hair dyes, shampoo/conditioners, and consumer items (eg, hair appliances, glasses). LIMITATIONS: Tertiary referral population. CONCLUSION: Isolated scalp involvement was less likely to be associated with allergic contact dermatitis than when adjacent anatomic sites were involved. Overlap with multiple diagnoses was frequent, including seborrheic dermatitis, irritant dermatitis, other dermatoses, or all 3. p-Phenylenediamine was the most common allergen.