A Case of Fulminant Ehrlichiosis in the Setting of Recent Trimethoprim-Sulfamethoxazole UseSlack, Donald III MD,*; Emmons, Wesley MD†Infectious Diseases in Clinical Practice: March 2013 - Volume 21 - Issue 2 - p 141–144 doi: 10.1097/IPC.0b013e3182699194 Case Reports Abstract In Brief Author Information Abstract: Transmitted by the Lone Star tick, Ehrlichia chaffeensis is the obligate intracellular organism responsible for human monocytic ehrlichiosis. During the last several years, a small number of case reports have surfaced in the literature that suggest a direct relationship between trimethoprim-sulfamethoxazole (TMP-SMX) use and the degree of morbidity in acute ehrlichiosis. In this article, we describe a patient who presented in the month of June to a small hospital in Delaware with overwhelming sepsis, toxic shock syndrome–like illness, after recent TMP-SMX use for a urinary tract infection. On transfer to our facility, our patient was treated promptly with doxycycline and improved significantly during the remainder of her stay. It is entirely possible that the severity of presentation seen in this case is related to this patient’s exposure to TMP-SMX in the setting of ehrlichiosis. Rarely, Ehrlichiosis can present as a fulminant process. Prior reports suggest that concomitant exposure to trimethoprimsulfamethoxazole and E. chafeensis may be associated with greater morbidity from this infection. Slack and Emmons describe a case in which such dual exposure was found, and discuss the possibility of mechanisms by which trimethoprim-sulfamethoxazole may precipitate a fulminant presentation of Ehrlichiosis. They hope that this case will help increase awareness of this potentially life-threatening combination of exposures to physicians treating such illness and to prevent further cases from occurring in the future. From *Internal Medicine and Infectious Disease, Christiana Care Health System, Newark, DE. Correspondence to: Donald Slack, III, MD, Department of Internal Medicine, Christiana Hospital, 4755 Ogletown-Stanton Road, Newark, DE 19718. E-mail: firstname.lastname@example.org. The authors have no funding or conflicts of interest to disclose. © 2013 by Lippincott Williams & Wilkins.