Expanding Patch Testing Beyond the Baseline Series: Usefulness of Customized Antimicrobials, Vehicles, and Cosmetics Series.

BACKGROUND: Testing cosmetics and their ingredients is essential to avoid missing relevant allergens and to monitor fluctuating incidence of hypersensitivity. OBJECTIVE: The aim of this study was to review the usefulness of patch testing with a customized antimicrobials, vehicles, and cosmetics (AVC) series over 15 years at a single Canadian site. METHODS: Between January 1, 2005, and December 31, 2019, patients suspected of having cosmetics allergy were patch tested with a 40-allergen AVC series in addition to the North American Contact Dermatitis Group standard screening series. We reviewed the patch test results of 2868 patients. RESULTS: We consecutively patch tested with the baseline series 6103 patients, of which 2868 (47%) were also tested with the AVC series. Of 53 different allergens that were tested at some point, 26 remained in the series throughout the 15-year span. The most common positive allergens were thimerosal (4.52%), polyvidone-iodine (2.25%), propolis (2.06%), sodium metabisulfite (1.94%), dodecyl gallate (1.53%), carmine (1.10%), lauryl glucoside (1.01%), sandalwood oil (0.7%), and tert-butylhydroquinone (0.7%). CONCLUSIONS: Although the expansion of the North American Contact Dermatitis Group standard screening series has decreased the yield from the AVC series from 21.1% to 13.9%, it still remains a useful adjunct for patients suspected of having cosmetics or disinfectants allergy.

Hypopigmented segmental Darier disease.

BACKGROUND: Darier disease is a genodermatosis caused by a mutation in the ATP2A2 gene. It classically presents as hyperkeratotic greasy papules in a seborrheic distribution. Several variants have been reported, notably the hypopigmented variant, which predominantly targets dark-skinned individuals, and a segmental variant that often follows the lines of Blaschko. METHODS: We report a case of a 41-year-old African-Canadian female with a long-standing history of macular hypopigmented pruritic eruption following the lines of Blaschko on her back. The eruption was persistent and recalcitrant to various treatments. Dyskeratosis with corps ronds and grains, acantholysis, and parakeratosis were observed on histopathology. Those findings were consistent with the diagnosis of segmental hypopigmented Darier disease. RESULTS AND CONCLUSIONS: To our knowledge, this is the first case reporting a combined segmental and hypopigmented variant of Darier disease. We further present a literature review for hypopigmented and segmental variants of Darier disease.