Angioedema is a rare but potentially life-threatening adverse effect of antipsychotics. The late-onset angioedema is a rare clinical condition which occurs months or years after.

To describe the case of a female patient who developed late-onset angioedema following treatment with clozapine after 5 years and redevelopment of angioedema with introduction of olanzapine which resolved on discontinuation of both drugs.

A case report

27-year-old woman was diagnosed with psychotic disorder and mental retardation five years ago. Her clinical condition was going well with clozapine 150 mg/day. At one of her follow-up visits, the physical examination revealed swelling over the face and eruption on perioral region. A diagnosis of ‘acute angioedema’ was established. After discontinuation of clozapine, skin symptoms were resolved within one week and olanzapine was started. Few days after introduction of olanzapine, the same skin symptoms emerged over the face and repeated laboratory tests were unremarkable. Skin scratch test revealed hypersensitivity with the medications of clozapine, olanzapine and sulpiride. Olanzapine discontinued and quetiapine 900 mg/day was started. She remained well under quetiapine therapy without any recurrence of psychiatric symptoms or angioedema.

To our knowledge, this is the first reported case of late-onset angioedema due to clozapine monotherapy. This case report indicates the need for clinicians to be aware of late-onset adverse events in patients treated with antipsychotics.