CD15 Diving into wetsuit contact allergy secondary to black rubber

Abstract We report the case of a 62-year-old man who developed a generalized eczematous dermatitis while scuba diving, which became apparent upon removing his wetsuit. Despite this initial reaction occurring 2 years prior, he continued to experience persistent, well-demarcated dermatitis around his waistband, along with intermittent patches on his trunk and limbs. He had a history of atopic eczema but no other significant medical conditions. His occupation was in film editing. Patch testing revealed positive reactions by 96 h to black rubber mix (0.6% in petrolatum) and N-isopropyl-N-phenyl phenylenediamine (IPPD) (0.1% in petrolatum) within the British Society for Cutaneous Allergy’s baseline series. Further positive reactions were noted to IPPD (0.25%) and cyclohexyl-N-phenyl-4-phenylenediamine (1%) in the rubber series. Additionally, he reacted to aminoazobenzene and Disperse Blue 35 in our textile series, dyes commonly found in synthetic fibre garments. Wetsuits are primarily composed of neoprene, a flexible, buoyant synthetic rubber. Thiourea-based rubber accelerators enhance the vulcanization process in neoprene-containing products and are known contact allergens. However, thiourea mix testing was negative in this patient. IPPD is a well-established screening allergen for black rubber. Black rubber mix, in use for patch testing since 1971, contains IPPD, N-cyclohexyl-N-phenyl-4-phenylenediamine, and N,N-diphenyl-4-para-phenylenediamine antioxidants, which also contribute to the material’s black–grey colour. Contact allergy to black rubber is most commonly associated with gloves and footwear, as well as vehicle tyres. While black rubber components are present in diving equipment, there have been no previous reports of allergic contact dermatitis from wetsuits. The patient was advised to contact wetsuit manufacturers to verify the absence of black rubber before purchasing a replacement. Given that elasticized clothing can contain hidden black rubber components woven into fabric, it was suspected that his persistent waistband dermatitis might have been exacerbated by elasticized or dyed synthetic fibres. He was therefore advised to opt for drawstring garments and avoid clothing containing Disperse Blue 35 (dark blue) and aminoazobenzene (yellow–orange) dyes. To our knowledge, this represents the first reported case of allergic contact dermatitis to black rubber mix components in a wetsuit.