A baseline patch test series for New Zealand.

BACKGROUND: Patch testing is the gold standard diagnostic test for allergic contact dermatitis and needs to be relevant to the region and the population being tested. The aim of this study was to develop a specific New Zealand baseline series (NZBS). METHOD: We performed a retrospective case note review of patients attending four regional patch test centres between 2008 and 2020. Demographic and diagnostic information was collected for each patient along with results of patch testing. Using the results of this review, a group of 11 dermatologists with an interest in contact dermatitis agreed on a core group of allergens for inclusion in an NZBS, based on the frequency of positive reactions and allergens of interest. The remaining potential allergens were ranked by each dermatologist using an online questionnaire, with inclusion in the final NZBS by consensus. RESULTS: Results from 2402 patients (67% female, mean age 44 years) from Auckland, Wellington, Palmerston North and Christchurch were collated. The 10 most frequent positive (relevant and non-relevant) allergens were nickel sulfate (22.0%), fragrance mix I (8.6%), cobalt chloride (7.3%), Myroxylon pereirae (5.6%), colophonium (5.1%), p-phenylenediamine (4.9%), methylisothiazolinone/methylchloroisothiazolinone (4.1%), fragrance mix II (3.9%), potassium dichromate (3.5%) and methylisothiazolinone (3.4%). Based on these results, a core series of 30 allergens was developed, with an additional 30 allergens added to form the extended series (total 60 allergens). CONCLUSION: The baseline series of patch test allergens for routine use in New Zealand (NZBS) is based on national patch test data and expert consensus.

Patch testing in New Zealand: Barriers to evidence-based care.

Allergic contact dermatitis is a disabling condition, significantly impacting on quality of life, which can only be alleviated by identification and avoidance of a relevant allergen. Patch testing remains the gold standard diagnostic test for allergic contact dermatitis. The consistency with which patch testing is used varies throughout the world. The purpose of this study was to look at the adequacy of current patch testing practice in New Zealand. We undertook literature review of current guidance regarding patch testing and created a web-based survey to evaluate use of patch testing in New Zealand. This was sent to all 75 vocationally registered New Zealand dermatologists. Of respondents, 46% do not perform patch testing. The most commonly cited barriers were lack of nursing support, poor remuneration, time pressure and lack of facilities. 23% noted that public patch testing services are not available in their region. The majority do not record patch test results in a database. Access to and utilisation of patch testing in New Zealand is suboptimal. Increasing services in the public sector requires investment by health boards, as there remains a dermatology workforce shortage in New Zealand. In private practice, patients often find it unsatisfactory to pay for negative tests, and adequate remuneration of patch testing by private insurers is necessary. Surveillance of patch test results at a national level is lacking, and the development of a centralised database to identify common allergens affecting our population is recommended.

Determinants of hand dermatitis, urticaria and loss of skin barrier function in professional cleaners in New Zealand.

This study assessed the risk of dermatitis, urticaria and loss of skin barrier function in 425 cleaners and 281 reference workers (retail workers and bus drivers). Symptoms, atopy and skin barrier function were assessed by questionnaire, skin prick tests, and measurement of transepidermal water loss. Cleaners had an increased risk of current (past 3 months) hand/arm dermatitis (14.8% vs. 10.0%; OR = 1.9, p < 0.05) and urticaria (11% vs. 5.3%; OR = 2.4, p < 0.05) and were more likely to have dermatitis as adults (17.6% vs. 11.4%; OR = 1.8, p < 0.05). The risk of atopy was not increased, but associations with symptoms were more pronounced in atopics. Transepidermal water loss was significantly higher in cleaners. Wet-work was a significant risk factor for dermatitis and hand washing and drying significantly reduced the risk of urticaria. In conclusion, cleaners have an increased risk of hand/arm dermatitis, urticaria and loss of skin barrier function.