Abstract / Summary
American cutaneous leishmaniasis (ACL) is a neglected tropical disease that is endemic in French Guiana. While the proportion of treatment failures is high, the risk factors are poorly understood. Although histological analysis of ACL has been described, few studies have investigated its correlation with severity or response to treatment in America. Our objectives were to provide a precise dermatological description of the clinical forms, investigate the association between histological and clinical characteristics, and determine their links with treatment failure to guide new therapeutics. Among the 1,577 patients with positive analysis for cutaneous leishmaniasis in French Guiana between 2016 and 2024, 268 patients with available histological examination were included, of whom 245 had a confirmed ACL diagnosis with 80 pictures available. A negative parasite load was associated with large lesions (> 3 cm), gold mining and immunosuppression. The presence of papular lesions, more than five lesions and lower limb involvement were significantly associated with a poorer response to treatment. When classified according to the picture-based classification, the papulo-nodular form tended to exhibit an anergic histological pattern and a poorer response to treatment. The bacterial-infection-like form tended to have a neutrophilic folliculitis pattern. For 21 patients with negative parasitological tests, histopathology allowed to correct the diagnosis. The sensitivity of histopathology was 82%. Therefore, this study shows that histopathology remains useful in atypical ACL, to confirm the diagnosis and determine the histological pattern. Targeted therapies (increased doses of antiparasitic drugs for papulo-nodular forms or neutrophils inhibitors for bacterial-like forms) could be guided by histopathology.