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.

Photopatch Testing in New Zealand: A 12-Year Retrospective Review.

BACKGROUND: Little is known about the common photoallergens in New Zealand, where ultraviolet exposure is particularly high. Availability of photopatch testing is limited because of it being performed in very few tertiary referral and contact dermatitis clinics. OBJECTIVE: To review the photopatch testing experience in New Zealand. METHOD: A retrospective review of all patients who underwent photopatch testing at a tertiary referral center in Auckland from 2008 to 2019 was performed. RESULTS: Seventy patients had photopatch testing over the 12-year period. Of the 58 patients tested using the photoallergen series, 6 (10%) patients had a positive photopatch test reaction, of which 4 were to promethazine and 2 were to benzophenone-3. The most common postpatch diagnosis was endogenous dermatitis (54%), followed by allergic contact dermatitis (21%), photoallergic contact dermatitis (9%), and chronic actinic dermatitis (4%). CONCLUSIONS: Both patch and photopatch testing are important investigations in patients with suspected photoallergic contact dermatitis. Promethazine and benzophenone-3 were the most frequent and only photoallergens in our population. Promethazine sensitization was via oral exposure, supporting a mechanism of systematized photoallergy to promethazine.

Bullous systemic lupus erythematosus responding to dapsone.

A 29-year-old woman with a 4-week history of systemic lupus erythematosus presented acutely with a severe generalized tense vesicular and bullous eruption with involvement of mucosal surfaces. At the time of her initial diagnosis of systemic lupus erythematosus, she had declined treatment, preferring to explore complementary medical therapies. Skin biopsy showed subepidermal blister formation with inflammation at the dermoepidermal junction. Direct immunofluorescence revealed strongly positive linear deposition of IgG and IgM, and positive linear granular deposition of IgA along the basement membrane zone. Electron microscopy showed that the level of the basement membrane split was below the lamina densa. A diagnosis of bullous systemic lupus erythematosus was made and dapsone was commenced, with a dramatic improvement in her skin eruption. The patient again declined further treatment of her systemic disease and sought complementary therapies, and subsequently presented with cerebral involvement.