Ear dermatitis after wearing ear rings: Rhodium hypersensitivity as the trigger

Rhodium is a metal widely used in jewellery with very few published cases involving it, the majority being rhinitis and occupational asthma.1 More widespread use could mean greater exposure, which could lead to a greater number of cases of dermatitis after contact with that metal2 or from its use in dental prostheses.3 A 26-year-old female came to our Allergy Department referring ear lobe eczema with pruritus (see Figure 1) after wearing a unique nickel-free rhodium ear ring (with no other metals listed in its composition). We performed a patch test (TrueTest®;Smart Practice) using the standard series recommended by the Spanish Contact Dermatitis and Skin Allergy Research Group4 and with rhodium(III) chloride hydrate (2% pet3; chemotechnique diagnostics) and following the interpretation recommendations of the European Society of Contact Dermatitis.5 After 48 and 96 h the Standard patch test was negative. However, the rhodium chloride patch test was positive both times(++; moderate local papules, vesicles, erythema and pruritus). Ten healthy patients were tested with a negative result. Rhodium is wrongly classified as a non-allergenic metal, because there are several reports of positive studies in metal workers,6 indicating that this metal is neither innocuous nor non-allergenic. An increase in the incidence of metal sensitisation has been published and we need to know how to respond to this sensitisation.7 This allergenic nature was demonstrated in a very interesting publication8 where the authors defined the genotoxicity and in vitro changes after rhodium contact, describing the immunotoxicity of rhodium as lower than that of palladium and platinum. In another study,9 IL-10 and IFN-gamma levels were higher in patients with contact dermatitis induced by nickel, rhodium or palladium, demonstrating another diagnostic tool to confirm metal contact dermatitis. As has been described in a clinical report,10 we have to inform our patients about the possible presence of alloys not listed in the item's composition, as patients have been found with sensitisation to metals not stated in the jewellery's composition, who get better if they do not use these products. To conclude, we present a patient with ear dermatitis after rhodium earring use (Figure 1). No previous reports have been published on this sensitisation. I. Garcia-Nunez: Investigation; conceptualization; writing – original draft; methodology; visualization; validation; data curation; software; project administration; funding acquisition. M. A. Algaba-Marmol: Writing – review and editing; supervision; resources; formal analysis. The authors declare that they have no conflicts of interest.