CD08 Occupational asthma and allergic contact dermatitis in a toolmaker

Abstract A 51-year-old atopic female toolmaker presented with recurrent dermatitis affecting her hands, forearms and face, episodic facial and lip swelling, breathlessness and wheezing. She had worked in a metal workshop for 30 years, and her symptoms began within 2 weeks of relocating to a new work facility, where she was involved in metal grinding and etching. Despite wearing gloves, she developed pruritic rashes, facial swelling and wheezing late in the working day, requiring repeated courses of oral corticosteroids. Her symptoms improved when away from work and resolved completely after transitioning to an office-based role. The respiratory team confirmed occupational asthma, based on work-related peak flow variability and elevated fraction of exhaled nitric oxide, both of which normalized in her office-based role, in conjunction with her clinical presentation and exposures to known asthmagens [Iskandar IYK, Gawkrodger DJ, Byrne L et al. Trends in work-related respiratory diseases attributed to nickel, chromium and cobalt in the UK: descriptive findings from The Health and Occupation Research (THOR) network 1996–2019. Occup Environ Med 2024; 81: 220–4]. Metalworking fluid was identified as the new exposure likely responsible for her respiratory presentation. Patch testing using the British Society for Cutaneous Allergy standard series, along with local metal, oils and cosmetic series, revealed positive reactions to metals (cobalt, nickel, palladium), rubber chemicals (thiuram mix, para-phenylenediamine) and preservatives [methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI)]. She confirmed occupational exposure to nickel and cobalt from metal grinding, isothiazolinones from metalworking fluids, and rubber accelerators from gloves. She was diagnosed with occupational ACD. The UK SWORD (Surveillance of Work-Related and Occupational Respiratory Disease) scheme attributed 1% of occupational respiratory diseases to nickel, chromium or cobalt, with most cases being occupational asthma, due to inhalation of fine metal dust generated from hard metal manu­facturing. Workers frequently report cough, wheezing and dyspnoea, which improve away from work. Occupational ACDs are common in metalworkers; common allergens include nickel, cobalt, chromium, rubber accelerators and preservatives from metalworking fluids (including MCI and MI) [Schubert S, Brans R, Reich A et al. Contact sensitization in metalworkers: data from the information network of departments of dermatology (IVDK), 2010–2018. Contact Dermatitis 2020; 83: 487–96]. This case highlights the coexistence of ACD and occupational asthma, conditions with distinct immunological mechanisms. ACD is a type IV hypersensitivity reaction, while occupational asthma is type I hypersensitivity. Their simultaneous presentation is rare, and patch testing, although primarily used for type IV hypersensitivity, provided supporting evidence for occupational asthma by confirming significant exposure to known respiratory sensitizers for which skin prick or IgE testing is not available.