Leishmaniasis is a chronic protozoan disease caused by the transmission of the intracellular parasite Leishmania spp. Its main reservoir is dogs and it is transmitted through the bite of female mosquitoes of the Phlebotomus family.1, 2 Leishmania infantum is the species responsible for the high prevalence of asymptomatic carriers in the Mediterranean endemic area, with humans acting as accidental reservoirs of this parasite that invades the mononuclear phagocyte system.3 According to the Red Nacional de Vigilancia Epidemiológica [Spanish National Epidemiological Surveillance Network] (RENAVE), 1359 autochthonous cases were reported between 2014 and 2017, with the Valencian Community top of the list (471, 34.7%).4 The latest data published by Public Health indicate an increasing incidence rate in recent years, reaching 4.20 per 105 inhabitants in the Valencian Community during 2019.5

The clinical presentation of infection and/or reactivation depends on the Leishmania subclass and the host immune response, with three possible clinical forms (Table 1). Despite being a widespread infection, its manifestations are almost exclusive to patients with impaired cellular immunity (children, HIV, transplant recipients or patients undergoing immunosuppressive therapy),6, 7, 8 with patients with Crohn’s disease or ulcerative colitis being a potential risk group that has not been studied to date. There is evidence of its atypical presentation and refractory behaviour in immunosuppressed patients, with its diagnosis delayed due to the need for a correct differential diagnosis with other potential diseases.9, 10 Overall, early and effective treatment ensures a good prognosis in immunocompetent patients,11, 12 but there are currently no guidelines for immunocompromised patients. In this context, as patients with inflammatory bowel disease (IBD) in endemic areas may be asymptomatic carriers of Leishmania spp. with a risk of infection or reactivation, it is essential to understand its clinical course and correct approach.

Due to the rarity of cases in IBD patients, most have been described in the literature as case reports or case series. This study presents three cases of patients diagnosed and treated at our hospital along with a systematic review of the literature, with the aim of providing a case-based update on the management of Leishmania infection or reactivation in patients with IBD, from diagnosis to treatment.