D3.59 - Occupational Cobalt Contact Dermatitis: Clinical Profile and Work implications

Occupational allergic contact dermatitis (ACD) to cobalt is an underrecognized condition in various industries, particularly construction, where prolonged exposure is common. Cobalt sensitization can lead to chronic, multifocal skin lesions and significantly impair work ability. This study aimed to describe the occupational and clinical characteristics of patients with cobalt-induced ACD and assess its impact on occupational fitness.

This descriptive cross-sectional study reviewed all medical records of patients who consulted the occupational medicine department at La Rabta Hospital in Tunis between 1998 and 2019 for occupational ACD due to cobalt sensitization.

We included 102 patients, predominantly male (74.5%), with a median age of 44 ± 9.5 years and a median occupational seniority of 16 ± 8.9 years. The most represented sectors were construction (40.2%), textile (7.8%), transport (7.8%), and healthcare (6.9%). Most affected occupations were masons (27.5%), construction workers (7.8%), police officers or national guards (5.9%), bus drivers (4.9%), and automotive/aerospace industry workers (4.9%). Main occupational exposures included cement (38.2%), metal instruments or components (9.8%), detergents (8.8%), and used industrial oils and greases (5.9%). Personal atopy was reported in 22.5%, and previous allergic contact dermatitis in 10.8%. Cutaneous symptoms appeared after hiring in 91.8% of cases, with a median duration of 3.5 ± 6.3 years and occurred on workdays and improved on leaves in 53.9% of cases. It mainly affected hands (83.8%) and feet (35.4%), with multifocal involvement in 52% of cases. Polysensitization to other metals (chromium and/or nickel) was observed in 89.2% of cases. Patch tests positive for cobalt chloride were relevant in 54.9% of cases, more frequently in men (p=0.001), construction sector (p<0.001), and masons (p<0.001). The ACD to cobalt was a compensable occupational disease in 35.3% of cases and required workplace adjustments in 74.5% of cases.

Cobalt exposure, while less common than other metal allergens, can cause occupational contact dermatitis with significant impact on affected workers. Preventive measures, including exposure reduction and skin protection, remain crucial to limit morbidity.