Clozapine is an atypical anti-psychotic used in the treatment of schizophrenia and other psychotic disorders. It is associated with several side effects, namely, hematologic disorders, the more common being agranulocytosis. Some cases of eosinophilia have been described. This work describes a case of transient eosinophilia caused by clozapine.

Description of a clinical case.

A 22-year-old female patient, with a treatment resistant psychotic disorder initiated clozapine in a slow titration to 300 mg. Ten days after initiating clozapine, the patient presented with eosinophilia (started with 6.6 × 108/L and peaked at 10.0 × 108/L). Two weeks later, the patient presented with a skin rash in the arms and legs. The case was discussed with internal medicine service and other causes of eosinophilia were excluded. Since the eosinophilia was mild, the rash was not severe and the patient did not present any other symptoms or signs, it was not considered necessary to stop clozapine. During the next three months, with close monitoring, the eosinophilia and the skin rash slowly resolved.

This is a case of a patient who presented mild eosinophilia and skin rash, associated to clozapine, with spontaneous resolution. We draw attention to the need of close monitorization and exclusion of other causes of eosiniphilia and rash. Furthermore, other hematologic disorders should be considered besides agranulocytosis, namely eosinophilia, when prescribing clozapine.

The authors have not supplied their declaration of competing interest.