LAUSR

To the Editor: Eltrombopag is a thrombopoietin mimetic indicated for the treatment of chronic immune thrombocytopenia (ITP).1 Common adverse events associated with eltrombopag include nausea, diarrhea, myalgias, and transaminitis.2 Dermatologic toxicity has been rarely described with eltrombopag therapy.3,4 In this study, we report a case of a patient that developed an acneiform rash in which eltrombopag was the probable case. A 66-year-old woman was referred to our clinic for management of her long-standing history of ITP. She was diagnosed and previously managed at an outside facility. Although her platelet counts are consistently between 18 and 30 3 103/mL, she has been asymptomatic without any major bleeding events. She has been previously treated with corticosteroids, intravenous immunoglobulin, rituximab, azathioprine, and splenectomy. The patient recently presented with a platelet count of 16 3 103/mL, but asymptomatic, for which she initiated eltrombopag 50mg orally once daily.Within 10 days of starting the medication, she experienced new onset facial burning and pruritus with the development of an acneiform rash across her face. A review of the patient’s current medications was conducted; no new medications were recently initiated save for eltrombopag. The patient also denied changing body soaps, face washes, or detergents before and after the time of eltrombopag initiation. The patient was prescribed a trial of erythromycin 2% topical gel twice daily for the rash; the patient reported at follow-up that the rash did not respond to the topical antibiotic therapy. The patient subsequently selfdiscontinued eltrombopag because of the reaction and has elected not to undergo further treatment for her ITP. The rash improved in appearance and symptomology with eltrombopag discontinuation. Eltrombopag was a probable cause of the observed cutaneous toxicity based on a calculated Naranjo adverse drug reaction probability scale score of 5.5 Development of the acneiform rash occurred in our patient several days after initiating daily eltrombopag therapy. The temporal relationship with drug initiation, improvement of the rash upon drug discontinuation, and lack of any alternative causes led us to suspect eltrombopag as being the causative agent in this case of cutaneous toxicity. A phase III trial evaluating eltrombopag compared with placebo in ITP reported rash occurring in about 3% of patients (n 5 3) receiving eltrombopag; however, severity and rash description were not provided.1 Notably, 3% (n 5 1) of patients receiving placebo also reported rash in this trial. Previous cases of cutaneous toxicity have been reported with eltrombopag and romiplostim; another thrombopoietin mimetic indicated for ITP. Cases of eltrombopag-associated dermatologic adverse events have been described as pruritic erythroderma or exanthem.3,4 Erythematous rash has been previously reported with romiplostim.6 Although rare, dermatologic toxicity with thrombopoietin mimetics can represent a unique adverse event for patients and practitioners. Supportive care and potential drug discontinuation may be considered to manage this adverse event as clinically indicated.