Contact Allergy Cross-reactions and Thresholds: A Review.

ABSTRACT: Consideration of contact allergen concomitant reactivity, which encompasses cross-reactors, co-reactors, and pseudo cross-reactors, is an important aspect of patient care, yet information on how these terms are differentiated and used in clinical practice is lacking. In this review, we provide definitions of cross-reactors, coreactors, and pseudo cross-reactors and discuss the utility of the American Contact Dermatitis Society Contact Allergen Management Program database cross-reactor groupings. We also discuss limitations to the current categorization of cross-reactivity and recommend incorporating new terms, including "apparent cross-reactor" and "derivative cross-reactor," when classifying cross-reactors.

Occupational Contact Dermatitis in Dental Personnel: A Retrospective Analysis of the North American Contact Dermatitis Group Data, 2001 to 2018.

BACKGROUND: Dental personnel are at risk of developing occupational contact dermatitis. OBJECTIVES: The aims of the study were to determine prevalence of occupational contact dermatitis in dental personnel referred for patch testing and to characterize relevant allergens and sources. METHODS: The study used a retrospective, cross-sectional analysis of the North American Contact Dermatitis Group (NACDG) data, 2001-2018. RESULTS: Of 41,109 patients, 585 (1.4%) were dental personnel. Dental personnel were significantly more likely than nondental personnel to be female (75.7% vs 67.4%, P < 0.0001), have occupationally related dermatitis (35.7% vs 11.5%, P < 0.0001), and/or have primary hand involvement (48.6% vs 22.5%, P < 0.0001). More than one quarter of dental personnel (62/585, 27.7%) had 1 or more occupationally related allergic patch test reaction(s). There were 249 occupationally related reactions to NACDG screening allergens, most commonly glutaraldehyde (18.1%), thiuram mix (16.1%), and carba mix (14.1%). The most common sources of NACDG screening allergens were gloves (30.7%), dental materials (26.6%), and sterilizing solutions (13.1%). Seventy-three dental personnel (12.5%) had 1 or more positive patch test reactions to occupationally related allergen(s)/substances not on the screening series. Occupationally related irritant contact dermatitis was identified in 22.2% (n = 130) of dental personnel, most commonly to nonskin soaps/detergents/disinfectants (32.0%). CONCLUSIONS: Occupational contact dermatitis is common in dental personnel referred for patch testing. Comprehensive testing beyond screening series is important in these patients.

Formaldehyde in Electronic Cigarette Liquid (Aerosolized Liquid).

BACKGROUND: Aerosolized liquid (e-liquid) of electronic cigarettes can be toxic. Beyond the solvent (propylene glycol, vegetable glycerin) and nicotine, little is known about the liquid composition. Formaldehyde, a carcinogen and source of contact dermatitis, has been reported in the vaporized e-liquid, but no studies have assessed the actual e-liquid. OBJECTIVE: The aim of the study was to evaluate e-liquid products for the presence of formaldehyde. METHODS: Sixteen e-liquid products were purchased and analyzed for the release of formaldehyde using the chromotropic acid method of detection. RESULTS: Of the 16 e-liquids purchased, 4 (25%) were positive for the presence of formaldehyde; 2 were flavored and 2 were nonflavored. All positive e-liquids were in pods or disposable electronic cigarette devices, and 2 were purchased from local vape shops. The average nicotine content in the positive e-liquids was 3.85% versus 4.03% in the negative e-liquids. CONCLUSIONS: The e-liquid products contain toxic chemicals not declared on product labels, as shown in this study with 25.0% of e-liquids containing formaldehyde. All positive e-liquids were within pods or disposable devices. Continued analysis of e-liquids and increased product regulation are needed.

Patch testing with ammonium persulfate: The North American Contact Dermatitis Group Experience, 2015-2018.

BACKGROUND: Ammonium persulfate (APS), an oxidizing agent used in hair products, manufacturing, and pool/spa water, can cause skin reactions, including allergic contact dermatitis. OBJECTIVE: To characterize positive patch test reactions to APS (2.5% petrolatum). METHODS: Retrospective analysis of patients tested to the North American Contact Dermatitis Group screening series from 2015 to 2018. RESULTS: Of 10,526 patients, 193 (1.8%) had positive patch test reactions to APS. Compared with APS-negative patients, APS-positive patients were significantly more likely to be male (43.2% vs 28.0%; P < .0001); have primary hand dermatitis (30.2% vs 22.0%; P = .0064), scattered generalized dermatitis (25.5% vs 17.9%; P = .0064), or trunk dermatitis (8.9% vs 4.9%; P = .0123); and have dermatitis that is occupationally related (22.2% vs 10.9%; P < .0001). More than half of the APS-positive reactions were currently relevant (57.0%); 19 (9.8%) were related to occupation, especially hairdressers (68.4%). Swimming pools/spas (23.3%) and hair care products (19.2%) were the most common sources of APS. LIMITATIONS: Immediate reactions and follow-up testing were not captured. CONCLUSION: The proportion of patients positive to APS was 1.8%. APS positivity was significantly associated with male sex and hand dermatitis. Swimming pool/spa chemicals were important sources of APS exposure.

Contact Dermatitis Associated With Hair Care Products: A Retrospective Analysis of the North American Contact Dermatitis Group Data, 2001-2016.

BACKGROUND: Hair care products (HCPs) may cause both allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD). OBJECTIVES: The aims of the study were to determine the prevalence of HCP-associated ICD/ACD and to characterize relevant allergens. METHODS: This study is a retrospective analysis of North American Contact Dermatitis Group (NACDG) patch test data, 2001-2016. RESULTS: Of 38,775 patients tested, 3481 (9.0%) had positive patch test reactions associated with HCPs. The HCP-positive patients were significantly more likely to be female (79.9% vs 66.0%) and/or have primary sites of dermatitis on the face (32.0% vs 27.8%) or scalp (15.4% vs 2.2%) compared with the HCP-negative patients (P < 0.0001). Of 4908 HCP-associated positive patch test reactions, 86.9% (n = 4263) were due to allergens on the NACDG screening series; p-phenylenediamine (35.8%), methylisothiazolinone (9.7%), methylchloroisothiazolinone/methylisothiazolinone (8.7%), and cocamidopropyl betaine (5.9%) were the most frequent. Most reactions (87.7%, 3736/4263) were currently clinically relevant. The most common job associated with 366 occupationally related NACDG HCP-associated allergens was hairdresser/cosmetologist (71.9%). Two hundred eighty-two patients (0.7%) had ICD associated with HCPs. Shampoo/conditioners were the most frequent source of NACDG HCP-associated reactions (47.3%) and HCP-associated ICD (45.0%). CONCLUSIONS: Of the HCP-positive patients, 18.5% had HCP reactions to allergens not on the NACDG screening series, underscoring the importance of patch testing to expanded series in patients suspected of HCP allergy.

Patch Testing With Tocopherol and Tocopherol Acetate: The North American Contact Dermatitis Group Experience, 2001 to 2016.

BACKGROUND: Vitamin E (tocopherol) a naturally occurring mixture of antioxidants commonly used in topical skin care products, may cause allergic contact dermatitis. OBJECTIVE: The aim of this study was to characterize positive patch test reactions to tocopherol and tocopherol acetate. METHODS: This is a retrospective analysis of North American Contact Dermatitis Group patch test data to tocopherols (dl-α-tocopherol 100% and/or dl-α-tocopherol acetate 100%) from 2001 to 2016. RESULTS: Of the 38,699 patients patch tested to tocopherol and/or tocopherol acetate, 349 (0.9%) had positive reactions; of these, 87.6% were currently relevant. Most (51.4%) were weak (+) and/or not related to occupation (99.1%). Compared with tocopherol-negative patients, tocopherol-positive individuals were more likely to be female (72.5% vs 67.2%, P = 0.0355), have a final primary diagnosis of allergic contact dermatitis (74.2% vs 52.6%, P < 0.0001), and have dermatitis in a scattered generalized distribution (23.8% vs 18.2%, P = 0.0072); they were also less likely to have hand involvement (16.6% vs 22.3%, P = 0.0064). The most common source of tocopherol was personal care products, especially moisturizers. CONCLUSIONS: Positive patch test reactions to tocopherols were relatively rare given their widespread use. When positive, current clinical relevance was high. Tocopherol-positive patients were more likely to be female and presented with dermatitis on the face or in a scattered generalized pattern.

Cutaneous findings in Fanconi anemia.

BACKGROUND: Fanconi anemia (FA) is a genetic disorder that results in bone marrow failure, physical abnormalities, and solid organ malignancies. The diagnosis of FA is often delayed because the early disease characteristics have not been well established. OBJECTIVE: To outline the spectrum of cutaneous findings seen in patients with FA. METHODS: A cross-sectional study in which patients with FA received a full-body skin examination. Patient characteristics are summarized with mean (SD) for continuous and count (%) for categorical variables. Poisson regression and logistic regression models were used to examine the relationships between pigmentary changes and patient characteristics. RESULTS: At least 1 cutaneous pigmentary alteration was present in 96.8% of patients, most arising before the teenage years. The most common finding was café-au-lait macules. Other findings included hypopigmented macules, skin-fold freckle-like macules, extensive sun-exposed freckling, and both hypopigmented and hyperpigmented pigment macules. LIMITATIONS: Patients received a single assessment, so the number of pigmentary changes could not be assessed over time. CONCLUSIONS: Characteristic morphology of FA includes faint and ill-defined café-au-lait macules, hypopigmented skin-fold freckle-like macules and the concurrence of hypopigmented and hyperpigmented macules. The recognition of these findings could aid clinicians in making earlier diagnoses.

Efficient generation of monoclonal antibodies against peptide in the context of MHCII using magnetic enrichment.

Monoclonal antibodies specific for foreign antigens, auto-antigens, allogeneic antigens and tumour neo-antigens in the context of major histocompatibility complex II (MHCII) are highly desirable as novel immunotherapeutics. However, there is no standard protocol for the efficient generation of monoclonal antibodies that recognize peptide in the context of MHCII, and only a limited number of such reagents exist. In this report, we describe an approach for the generation and screening of monoclonal antibodies specific for peptide bound to MHCII. This approach exploits the use of recombinant peptide:MHC monomers as immunogens, and subsequently relies on multimers to pre-screen and magnetically enrich the responding antigen-specific B cells before fusion and validation, thus saving significant time and reagents. Using this method, we have generated two antibodies enabling us to interrogate antigen presentation and T-cell activation. This methodology sets the standard to generate monoclonal antibodies against the peptide-MHCII complexes.