Background: Piperazine is a secondary heterocyclic amine that may give rise to occupational asthma of uncertain mechanism.

Methods: We report on a 42-year-old woman, a process operator in a chemical factory, who developed workrelated symptoms of rhinitis and asthma upon exposure to piperazine citrate. She remained symptom free during holidays and days off work.

Results: Skin prick test with piperazine citrate was positive. Specific inhalation challenge with piperazine citrate at a concentration of 5 mg/m3 for 30 minutes elicited an isolated late asthmatic response. Airway hyperresponsiveness to methacholine significantly increased 3 hours after the piperazine challenge, preceding the late asthmatic response.

Conclusion: This patient had developed occupational asthma caused by piperazine, as confirmed by the specific inhalation challenge test, possibly due to an immunological mechanism.

Key words: Occupational asthma, piperazine, amines, specific inhalation challenge.