Olanzapine-induced vasculitis.
INTRODUCTION: Elderly patients are particularly vulnerable to adverse drug reactions as a result of polypharmacy and metabolic changes associated with aging. We present a case of leukocytoclastic vasculitis induced by olanzapine, a medication commonly used in elderly patients. CASE SUMMARY: An 82-year-old woman was admitted to the extended-care center for short-term rehabilitation after prolonged hospitalization for a pulmonary embolism requiring mechanical ventilation. The pulmonary problem resolved, but her hospitalization and subsequent rehabilitation were complicated by agitated delirium, which was treated with olanzapine and modification of contributory factors. At the time of admission to the rehabilitation facility, the patient had been receiving warfarin for 2 weeks and olanzapine for 6 days. On the eighth day after initiation of olanzapine, erythematous skin lesions developed on dependent areas. The international normalized ratio for warfarin was within the acceptable range; however, because warfarin has been associated with subcutaneous bleeding presenting as petechiae and ecchymosis, subcutaneous enoxaparin was substituted for warfarin. The skin lesions continued to worsen over the next week and developed into palpable lesions. Biopsy of the rash revealed leukocytoclastic vasculitis. In the absence of another cause, olanzapine was discontinued and the rash improved significantly. When the agitation recurred, risperidone was initiated, but the patient experienced dizziness with this agent. Olanzapine was resumed and the skin lesions recurred. Olanzapine was then changed to quetiapine, and the skin lesions improved over the next few weeks. DISCUSSION: Olanzapine is commonly used in elderly patients to control behavioral disturbances associated with dementia, delirium, and other psychiatric disorders. Leukocytoclastic vasculitis is an infrequently reported adverse drug reaction with olanzapine. Its exact pathogenic mechanism is unknown, but both cell-mediated and humoral immunity appear to play important roles. Because drug-induced vasculitis has an identical clinical presentation and identical serologic/pathologic parameters to idiopathic forms of vasculitis, a high index of suspicion is necessary for its accurate diagnosis. CONCLUSIONS: Because adverse drug reactions are common in elderly patients taking multiple medications, physicians should be vigilant when starting new medications and should attempt to eliminate unnecessary medications. Clinicians should be aware of the potential for leukocytoclastic vasculitis in association with olanzapine.