Dermal, respiratory and neurological effects following workplace exposure to diisopropylcarbodiimide

Diisopropylcarbodiimide is a peptide coupler commonly used in biotechnology. Dermal and respiratory effects, due to irritant and sensitizing properties, have been reported in exposed workers and experimental studies. Neurological toxicity, as demonstrated in animal studies, has not been reported in humans. We describe three male workers who experienced dermal, respiratory, and neurological sequelae after accidental exposure to diisopropylcarbodiimide, a volatile liquid product.

Clinical data were collected retrospectively through review of medical files and follow-up interviews. Each worker underwent a symptom-guided clinical evaluation, including dermatological, respiratory, neurological, and neuropsychological assessment. Follow-up extended up to three years, depending on the case.

Three workers were occupationally exposed to diisopropylcarbodiimide by inhalation and dermal contact due to a leaking barrel. All experienced similar clinical courses after the incident, including the development not only of contact dermatitis and occupational asthma, but also neurological effects (persistent headaches, neuropathic pain and paraesthesia in hands/feet, fatigue and cognitive impairment, compatible with chronic toxic encephalopathy). They also developed sleep disturbances, including new-onset obstructive sleep apnoea syndrome.

The consistency of these presentations across patients, the close temporal association to a brief exposure to diisopropylcarbodiimide, and evidence from animal studies suggest a possible causal relationship.

Three workers experienced contact dermatitis, occupational asthma, severe neurological sequelae, as well as new-onset obstructive sleep apnoea syndrome after occupational exposure to diisopropylcarbodiimide. The close temporal association to a single presumably high-level exposure suggests a possible causal relationship. To prevent such health consequences, workers with potential exposure to peptide couplers must be made aware of their hazards and adequately protected.