Phenotypic Characteristics of Occupational Asthma Caused by Persulfate Salts in Hairdressers: A Multicenter Cohort Study.

Summary

In a multicenter retrospective cohort of SIC-confirmed occupational asthma, hairdressers with persulfate-induced disease (n=107) had longer exposure before onset, more work-related rhinitis (76%), lower post-SIC FeNO (median 18 ppb), and more isolated late reactions than OA due to other LMW agents. These results delineate a distinct phenotype with potential diagnostic and management implications.

Key Findings

• PS-induced OA had longer exposure duration before asthma onset than OA due to other LMW agents.
• Higher prevalence of work-related rhinitis in PS-induced OA (76%) vs isocyanates (36%) and other LMW agents (53%), P<.001.
• Lower post-SIC FeNO in PS-induced OA (median 18 ppb) vs isocyanates (35 ppb) and other LMW agents (27 ppb), P<.001.
• Highest rate of isolated late asthmatic reactions (49%), significant vs other LMW agents (31%, P<.002).

Clinical Implications

Do not rely solely on FeNO to screen PS-induced OA; consider work-related rhinitis as a sentinel symptom and prioritize SIC where feasible. Implement exposure reduction (ventilation, PPE, product substitution) and earlier surveillance for hairdressers handling persulfates.

Limitations

• Retrospective design with potential selection and referral bias
• Generalizability limited to specialized centers; lack of longitudinal outcomes

Future Directions

Prospective studies to validate diagnostic thresholds, mechanistic profiling (e.g., non-eosinophilic pathways), and intervention trials on exposure reduction and protective measures in salons.