Does clinical testing support the current guidance definition of prolonged contact for nickel allergy?

BACKGROUND: The European Chemical Agency (ECHA) definition of prolonged contact was introduced in 2014 and has not been evaluated clinically. OBJECTIVES: To assess whether nickel-sensitized individuals react on patch testing with high nickel-releasing metal discs for short and repetitive periods. MATERIALS AND METHODS: We patch tested 45 nickel-sensitized individuals double-blind with 2 different types of high nickel-releasing discs for 10, 30 and 60 minutes on 3 occasions over a period of 2 weeks, and for 1 longer period. Discs were tested for nickel release. RESULTS: Nickel release from both discs significantly exceeded the 0.5 µg Ni/cm2 /week limit of the EU REACH nickel restriction. However, only 1 individual tested had a largely dose-dependent allergic reaction. CONCLUSIONS: The majority of nickel-allergic subjects did not react to nickel discs after 2 hours or after repetitive exposures of up to 30 minutes on 3 occasions over a period of 2 weeks. The length of time needed to cause nickel allergic contact dermatitis in most nickel-allergic individuals is longer than the ECHA guidance definition. Longer test times are needed to define the time required to cause dermatitis in most nickel-allergic individuals. As a limitation, the test conditions did not adequately assess real-life factors such as friction, which is relevant for some uses of nickel.

Occupational skin disease among Australian healthcare workers: a retrospective analysis from an occupational dermatology clinic, 1993-2014.

BACKGROUND: Healthcare workers (HCWs) are at risk of developing occupational skin disease (OSD). OBJECTIVES: To ascertain the causes of OSD in Australian HCWs in a tertiary referral clinic. METHODS: A retrospective review was performed of patients assessed at the Occupational Dermatology Clinic in Melbourne from 1993 to 2014. RESULTS: Of 685 HCWs assessed in the clinic over a period of 22 years, 555 (81.0%) were diagnosed with OSD. The most common diagnosis was irritant contact dermatitis (ICD) (79.1%), followed by allergic contact dermatitis (ACD) (49.7%). Natural rubber latex allergy was also relatively frequent (13.0%). The major substances causing ACD were rubber glove chemicals (thiuram mix and tetraethylthiuram disulfide), preservatives (formaldehyde, formaldehyde releasers, and isothiazolinones), excipients in hand cleansers, which are hard-to-avoid weak allergens, and antiseptics. ACD caused by commercial hand cleansers occurred more frequently than ACD caused by alcohol-based hand rubs (ABHRs). Occupational ICD was mostly caused by water/wet work and hand cleansers, and environmental irritants such as heat and sweating. CONCLUSIONS: Understanding the causes of OSD in HCWs is important in order to develop strategies for prevention. We suggest that skin care advice should be incorporated into hand hygiene education. The use of ABHRs should be encouraged, weak allergens in skin cleansers should be substituted, and accelerator-free gloves should be recommended for HCWs with OSD.

Allergic contact dermatitis to substitute hair dyes in a patient allergic to para-phenylenediamine: Pure henna, black tea and indigo powder.

We report a case of a 50-year-old lady with allergic contact dermatitis to para-phenylenediamine, who in her quest to find a substitute hair dye, subsequently reacted to a number of plant-based hair dyes, including pure henna, black tea and indigo powder respectively. While these substances all contain tannins, testing to possible constituents tannic acid and gallic acid was negative.