Pediatric Patch Testing at Mayo Clinic Between 2016 and 2020.

Background: Allergic contact dermatitis (ACD) is a common condition within the pediatric population. Patch testing is an important way to identify relevant allergens. Objective: To provide an update of the common contact allergens seen in children based on patch testing data at our institution from 2016 to 2020. Methods: We performed a retrospective analysis of patch test data from children aged 1-18 years from 2016 to 2020 at Mayo Clinic. Reaction rates were compared to the rates reported by the Pediatric Contact Dermatitis Registry (PCDR). Results: One hundred ninety-two children aged 1-18 were patch tested to various allergens. A total of 15,457 allergens were tested, with 291 positive tests. The top 5 allergens with highest positive reaction rates were hydroperoxides of linalool, hydroperoxides of limonene, methylisothiazolinone, nickel, and cobalt. Seven of the top 38 allergens with the highest reaction rates are not currently included in the Mayo Clinic Pediatric Patch Test Series, and 11 are not currently included in the Pediatric Baseline Series (as developed by the Pediatric Contact Dermatitis Workgroup). Conclusions: Patch testing is a useful tool to diagnose children with ACD. With new products and exposures, there is an opportunity to expand current pediatric patch testing series.

Systematic Identification of Copositivity Groups in Standard Series Patch Testing Through Hierarchical Clustering.

Importance: Patients are frequently copositive for multiple allergens simultaneously, either due to chemical similarity or simultaneous sensitization. A better understanding of copositivity groups would help guide contact avoidance. Objective: To use patient data to systematically determine copositivity groups in the Mayo Clinic Standard Series. Design, Setting, and Participants: In this retrospective cross-sectional analysis, the Mayo Clinic patch test database was queried for pairwise copositivity rates in the 80 allergen Mayo Clinic Standard Series between 2012 and 2021. Data were collected from 3 tertiary care sites of the Mayo Clinic Contact Dermatitis Group and a total of 5943 patients were included, comprising all patients undergoing patch testing to the Mayo Clinic Standard Series allergens. Main Outcomes and Measures: Copositivity rates between every 2 allergens in the 80-allergen Mayo Clinic Standard Series were estimated. After background correction, copositivity rates were analyzed using unsupervised hierarchical clustering to systematically identify copositivity groups in an unbiased manner. Results: Overall, 394 921 total patches were applied to 5943 patients (4164 [70.1%] women, 1776 [29.9%] men, with a mean [SD] age of 52.3 [18.8] years ), comprising 9545 positive reactions. After background correction based on overall positivity rates, hierarchical clustering revealed distinct copositivity groups. Many were supported by prior literature, including formaldehyde releasers, cobalt-nickel-potassium dichromate, acrylates, 3-dimethylaminopropylamine-amidoamine-oleamidopropyl dimethylamine, alkyl glucosides, budesonide-hydrocortisone-17-butyrate, certain fragrances, compositae-sesquiterpene lactone mix, mercapto mix-mercaptobenzothiazole, carba mix-thiuram mix, and disperse orange-p-phenylenediamine. However, novel associations were also found, including glutaraldehyde-sorbitan sesquioleate, benzalkonium chloride-neomycin-bacitracin, bronopol-methylchloroisothiazolinone-methylisothiazolinone, and benzoic acid-iodopropynyl butylcarbamate. Conclusions and Relevance: This retrospective cross-sectional analysis found that copositivity rates varied between allergens; allergens with extremely high positivity rates demonstrated nonspecific copositivity to multiple other allergens. Background correction based on positivity rates followed by hierarchical clustering confirmed prior known copositivity groups, contaminants and/or excipients leading to copositivity, and novel associations to guide contact avoidance.

Trends in Patch Testing With the Mayo Clinic Standard Series, 2017-2021.

Background: Patch testing to a standard series is used to identify culprit allergens in patients with contact dermatitis. The reaction rates evolve over time based on trends in cutaneous exposures by the general population. Objective: The aim of this study was to analyze the patch test results of the Mayo Clinic standard series in patients tested from 2017 to 2021. Methods: The patch test reactions of standard series allergens tested from 2017 to 2021 were retrospectively reviewed and compared with the results of our prior report from 2011 to 2015 as well as the North American Contact Dermatitis Group (NACDG) report from 2017 to 2018. Results: Of 2667 patients tested, 1683 (63.1%) had at least 1 positive reaction. The 15 allergens with the highest reaction rates were hydroperoxides of linalool 1%, nickel (II) sulfate hexahydrate, methylisothiazolinone, Myroxylon pereirae resin, hydroperoxides of linalool 0.5%, methyldibromo glutaronitrile, neomycin sulfate, cobalt (II) chloride hexahydrate, fragrance mix I, benzalkonium chloride, bacitracin, hydroperoxides of limonene, methylchloroisothiazolinone/methylisothiazolinone, p-phenylenediamine, and textile dye mix. Twelve (80%) of these allergens were also in the top 15 of the most recent NACDG report. Conclusions: Hydroperoxides of linalool and hydroperoxides of limonene are new allergens that have been added to our standard series. These are associated with high reaction rates.

Trends in Patch Testing of Black Patients: The Mayo Clinic Decade Experience (January 1, 2011, to December 31, 2020).

Background: Trends in patch testing for allergic contact dermatitis (ACD) have not been well characterized in Black patients. Despite similar incidence of ACD in Black and White patients, there are differences in allergen profiles. Understanding patch testing trends in Black patients furthers knowledge that has considerable impact on the management of ACD in the Black population. Objective: The purpose of this study was to review the results of patch testing in Black patients at Mayo Clinic over a decade. Methods: We retrospectively reviewed the results of patch testing to the standard, extended standard, or hairdresser series in 149 Black patients seen at Mayo Clinic (Rochester, MN; Scottsdale, AZ; and Jacksonville, FL) from January 1, 2011, to December 31, 2020. Results: During the 10-year period, 149 Black patients (mean age, 49.2 years [SD, 17.1 years]; female 67.1%) were patch tested at Mayo Clinic to the standard, extended standard, or hairdresser series. Most common sites of dermatitis were generalized (30.9%), hands (18.8%), leg (16.8%), trunk (16.1%), and arm (14.8%). Overall, 109 patients (73.2%) had at least 1 positive reaction and 74 patients (50%) had 2 or more positive reactions. Overall, the 10 allergens with the highest reaction rates (from highest to lowest) identified in our study population were 4-amino-2-hyroxytoluene (33.3%), thimerosal (20.4%), nickel sulfate (18.9%), methylisothiazolinone (16.5%), methyldibromo glutaronitrile (13.4%), methyldibromo glutaronitrile/phenoxyethanol (12.5%), captan (12.5%), carmine (12.5%), methylchloroisothiazolinone/methylisothiazolinone (11.5%), and hydroperoxide of linalool 1% (11.3%). Conclusions: We describe patch test results in Black patients over a decade at Mayo Clinic. The top 10 allergens were preservatives, hair dyes, and fragrances. Differing patterns of allergens may occur in Black patients due to different patterns of exposures related to cultural practices.

"Look Beyond the Skin": A case report about chronic pruritus.

A healthy 23-year-old female developed generalized pruritus over a year that began on her feet and gradually progressed to involve more than 50% of her entire body surface area. Punch skin biopsies were inconclusive, whereas a two-view chest x-ray was suspicious for lymphadenopathy. A chest computed tomography scan with contrast identified an anterior mediastinal mass which was biopsied and diagnosed as a nodular sclerosis type of Hodgkin's lymphoma. Subsequently, appropriate therapy was initiated resulting in complete resolution of the patient's chronic itch. This case underscores the clinical significance of a comprehensive systemic evaluation in chronic pruritus of unclear etiology.

Reevaluating Corticosteroid Classification Models in Patient Patch Testing.

Importance: Individuals with allergic contact dermatitis to one topical corticosteroid may also react to other corticosteroids. Corticosteroid classification models have been proposed to predict such copositivity, recommend representative screening corticosteroids, and guide allergen avoidance. Objective: To use patient data to determine copositivity patterns between corticosteroids and evaluate against previous corticosteroid classification models. Design, Setting, and Participants: This qualitative study included a retrospective analysis of the Mayo Clinic Contact Dermatitis Group corticosteroid patch test data from 2010 to 2019. Among patients undergoing patch testing with the Mayo Clinic's standard or steroid series who consented to research participation, 5637 patients were included in the analysis. Copositivity rates were determined between corticosteroids and analyzed by hierarchical clustering for comparison to previous classification models. Main Outcomes and Measures: The frequency of patch test positivity to each of the analyzed corticosteroids was noted and compared with previously published patch test positivity rates. Copositivity rates between each pair of corticosteroids were determined, and overall copositivity patterns were analyzed and evaluated against known steroid classes. Results: A total of 49 472 individual patches were applied to 5637 patients, testing 18 corticosteroids. Patch test positivity rates ranged between 0.3% and 4.7%. The fluocinonide positivity rate corresponded to the highest copositivity rate with other corticosteroids (mean [SD], 50.7% [26.1%]). Tixocortol-21-pivalate, 0.1%, and tixocortol-21-pivalate, 1%, positivity rates corresponded to the lowest copositivity rates (mean [SD], 4.1% [1.7%] and 3.6% [1.4%], respectively). Hierarchical clustering elucidated patterns that did not support previous corticosteroid classification models. Conclusions and Relevance: In this qualitative study, copositivity rates were variable between corticosteroids, and overall patch test positivity for allergy to topical corticosteroids was rare. Previously published corticosteroid classifications are not supported by real patient-derived data and may not be accurate in predicting corticosteroid copositivity.

Acral localized acquired cutis laxa as presenting sign of underlying systemic amyloidosis.

Acral localized acquired cutis laxa (ALACL) is a rare variant of acquired cutis laxa, and the clinical appearance is characterized by loose, redundant and wrinkled skin of the distal extremities. By definition, histopathology of affected tissue reveals sparse or fragmented elastic fibers. However, this can be difficult to assess on routine staining, and sometimes requires electron microscopy. The condition has been associated with plasma cell dyscrasias or recurrent inflammatory states. We present a case of a 65-year-old man who presented with enlarged and doughy finger pads. Skin biopsy showed diffuse dermal amyloid deposition displacing dermal stroma and reduction of elastic fibers, although these changes were subtle on routine hematoxylin and eosin staining. Mass spectrometry of laser capture microdissected tissue showed AL kappa-type amyloid and further workup revealed a diagnosis of primary systemic AL-kappa amyloidosis requiring bone marrow transplantation. This case represents an unusual presentation of acquired cutis laxa and highlights the need for a high index of suspicion when reviewing histopathology of this entity. In addition, the case highlights the importance of investigation into possible systemic associations, such as plasma cell dyscrasias.

Dental root abnormalities in four children with PHACE syndrome.

PHACE(S) syndrome is a condition characterized by posterior fossa malformations, hemangiomas, arterial anomalies, cardiac defects, eye abnormalities, sternal cleft, and supraumbilical raphe. We present four children with PHACE(S) syndrome who have absence of or severe malformation of the roots of their permanent first molars (PFMs). Root abnormalities in the children's molars were bilateral and not restricted to the segments affected by cutaneous hemangioma. The reason for root abnormalities is unknown, but given the rarity of these findings in healthy children, it is likely an additional dental manifestation of PHACE syndrome. The absence of functional roots in the PFMs can result in significant consequences. Therefore, we recommend a panoramic dental radiograph during transitional dentition for children with PHACE syndrome to screen for dental root abnormalities.

Online education improves pediatric residents' understanding of atopic dermatitis.

BACKGROUND/OBJECTIVES: Pediatricians manage skin conditions such as atopic dermatitis (AD) but report that their dermatologic training is inadequate. Online modules may enhance medical education when sufficient didactic or clinical teaching experiences are lacking. We assessed whether an online module about AD improved pediatric residents' knowledge and changed their clinical management of AD. METHODS: Target and control cohorts of pediatric residents from two institutions were recruited. Target subjects took a 30-question test about AD early in their residency, reviewed the online module, and repeated the test 6 months and 1 year later. The control subjects, who had 1 year of clinical experience but had not reviewed the online module, also took the test. The mean percentage of correct answers was calculated and compared using two-sided, two-sample independent t tests and repeated-measures analysis of variance. For a subset of participants, clinical documentation from AD encounters was reviewed and 13 practice behaviors were compared using the Fisher exact test. RESULTS: Twenty-five subjects in the target cohort and 29 subjects in the control cohort completed the study. The target cohort improved from 18.0 ± 3.2 to 23.4 ± 3.4 correctly answered questions over 1 year (P < .001). This final value was greater than that of the control cohort (20.7 ± 4.5; P = .01). Meaningful differences in practice behaviors were not seen. CONCLUSION: Pediatric residents who reviewed an online module about AD demonstrated statistically significant improvement in disease-specific knowledge over time and had statistically significantly higher scores than controls. Online dermatology education may effectively supplement traditional clinical teaching.

Eczema and Urticaria as Manifestations of Undiagnosed and Rare Diseases.

Eczema and urticaria are common disorders encountered in pediatric patients, but they may occasionally be the presenting complaint in a child with an underlying rare disease. Immunodeficiency syndromes should be suspected when eczema is associated with neonatal onset, recurrent infections, chronic lymphadenopathy, or failure to thrive. Nutritional deficiencies and mycosis fungoides are in the differential diagnosis for a child with a recalcitrant eczematous eruption. Autoinflammatory syndromes should be suspected in a child with chronic urticaria, fever, and other systemic signs of inflammation. Although these disorders are rare, early recognition allows for appropriate treatment and decreased morbidity for the child.