Early-Onset Drug Hypersensitivity Syndrome in a Man With Pneumonia Due to Pre-sensitization to Olanzapine

Abstract

Drug hypersensitivity syndrome (DHS) generally starts two weeks to two months after administration of certain drugs. Olanzapine has been reported to cause drug reaction with eosinophilia and systemic symptoms (DRESS), but rarely causes drug-induced hypersensitivity syndrome (DIHS). A 49-year-old schizophrenic man was hospitalized for pneumonia and developed DIHS/DRESS 10 days after starting olanzapine. Although reactivation of human herpesvirus 6, which is one of the diagnostic criteria for DIHS, was not confirmed, the diagnostic criteria for DRESS were met. The patient may have developed early-onset DIHS/DRESS because he was sensitized to olanzapine prior to hospitalization.

Keywords: adverse drug reaction; drug hypersensitivity syndrome; drug-induced hypersensitivity syndrome; olanzapine; skin rash.

Figure 1. Clinical course of the patient’s disease according to body temperature (BT) and the eosinophil count. The red dotted line shows the BT, and the blue line shows the eosinophil count.

BT, body temperature; Eos, eosinophil count; day, days since admission; mPSL, methylprednisolone; PSL, prednisolone; VCM, vancomycin; MEPM, meropenem; LVFX, levofloxacin.

Figure 2. Rash thought to have been caused by olanzapine-induced hypersensitivity. Skin eruption five days (a) and seven days (b), and 16 days (c) after the discontinuation of olanzapine (on days 25, 27, and 36 of hospitalization, respectively). Despite the discontinuation of olanzapine, the skin lesions worsened initially but subsequently resolved following the administration of steroids. Even though skin eruption began to improve on day 34, facial edema and erythema with desquamation of cheeks and periorbital area were still observed on day 36 (c).

Figure 3. Histopathologic findings of skin with no lesion (a) and skin with erythema (b). Findings of interface dermatitis with basal vacuolization, lymphocyte infiltration, and shedding of melanocytes from the basal layer to the dermis layer were observed (b).