Memory T helper cells identify patients with nickel, cobalt, and chromium metal allergy.

BACKGROUND: Patch testing is the gold standard for identifying culprit allergens in allergic contact dermatitis; however, it is laborious and positive reactions are difficult to quantitate. Development of complementary in vitro tests is, therefore, of great importance. OBJECTIVES: This study aimed to improve the in vitro lymphocyte proliferation test (LPT) to detect allergic responses to nickel (Ni), cobalt (Co), and chromium (Cr). METHODS: Twenty-one metal allergic patients with a positive patch test to Ni (n=16), Co (n=8), and Cr (n=3) and 13 controls were included. All were tested by a flow cytometric LPT. RESULTS: Metal-reactive cells were identified as T helper (Th) cells with high expression of the memory marker CD45RO. Skin-homing (cutaneous lymphocyte-associated antigen positive [CLA+]) Ni-reactive memory Th (Thmem hi ) cells identified individuals with a positive patch test for Ni with 100% sensitivity (95% confidence interval [CI] 81%-100%) and 92% specificity (95% CI 67%-100%). Moreover, Co-specific Thmem hi cells expressing CCR6 identified patients with a positive patch test for Co with 63% sensitivity (95% CI 31%-86%) and 100% specificity (95% CI 77%-100%). In Cr allergic individuals, Cr-reactive Thmem hi cells tended to increased CLA and CCR6 expression. CONCLUSION: Metal-reactive Th cells with high expression of CD45RO and coexpression of CLA and CCR6 improved the LPT, making it an attractive supplement to the patch test.

Natural ingredients in cosmetic products-A suggestion for a screening series for skin allergy.

BACKGROUND: Naturally derived cosmetic product ingredients of both plant and animal origin are being included increasingly in product formulations in order to cater to consumer preferences. They may be an overlooked cause of reactions to cosmetic products in some patients with dermatitis. OBJECTIVES: To identify naturally derived cosmetic product ingredients with allergenic potential (type I and type IV) and propose a cosmetic screening test series. METHODS: The study was conducted in two steps. The first step was a market survey using a nonprofit application helping consumers avoid problematic substances in cosmetic products. The application contained 10 067 cosmetic products that were label checked for naturally derived cosmetic product ingredients. The second step was a literature search to examine how frequently the naturally derived ingredients were described and related to allergic reactions in cosmetics or other topically administered products. RESULTS: We identified 121 different naturally derived cosmetic product ingredients that were included in at least 30 cosmetic products. In total, 22 ingredients were selected for a screening test series. CONCLUSIONS: We propose a supplemental patch test and a prick test screening series with naturally derived cosmetic product ingredients for patients with skin reactions to cosmetic products, aiming to identify a cause in more patients than is currently possible.

Highlights in allergic contact dermatitis 2018/2019.

PURPOSE OF REVIEW: The purpose was to highlight recent findings especially concerning new and old allergens, trends, diagnosis and causes of contact allergy. RECENT FINDINGS: Nickel is still the most frequent cause of contact allergy in women and piercings remain an important risk factor. Countries with a long history of regulation of contact allergens have the lowest level of contact allergy to nickel and chromium in Europe. Among the most frequent causes of fragrance contact allergy is terpenes, which are oxidized such as limonene, linalool and in some countries: geraniol. Methylisothiazolinone is still causing considerable problems due to hidden exposures. Acrylates are emerging allergens and 2-hydroxyethyl methacrylate has been included in the 2019 update of the baseline series, as many new cases are seen due to long-lasting nail polish based on acrylates and glue (isobornyl acrylate) in insulin pumps. More than 10 new allergens have been described, which need to be considered in diagnosing contact allergy. SUMMARY: Allergic contact dermatitis is a frequent problem, it also constitutes a challenge to diagnose due to many potential contact allergens. The main culprit allergens remain the same, new significant causes are found especially within acrylates.