INTRODUCTION:
In September 2023, fifty cases of chronic limb ulcers of unknown origin were reported in Northern Cameroon. This disease, locally called “Ladde”, was presumably transmitted by insect bites. We investigated to identify the cause and socio-anthropological considerations.

METHODS:
We conducted a descriptive cross-sectional study in November 2023. Cases were patients with chronic limb ulcers (≥4 weeks) living in Northern Cameroon between 2018-2023. We featured sociodemographic (sex, age, occupation), clinical (location, signs/symptoms, ulcer occurence), and therapeutic data (itinerary, treatment and outcome). We collected blood samples, ulcer swabs and skin biopsies to identify pathogens; performed socio-anthropological and entomological surveys.

RESULTS:
We identified 153 cases: 119 (77.8%) were men; median age: 38.5 years (9 months to 94 years). Farmers (n=63, 41.2%), and housewives (n=24, 15.7%) were most affected. Lower limbs (n=138, 90.2%) were the preferred location. Pain (n=130, 85%), swelling (n=113, 73.9%), ulceration (n=43, 28.1%) and fever (n=42, 27.5%) were the most frequent signs/symptoms. In 79 (51.6%) cases, the ulcers occurred spontaneously and 67 (43.8%) after trauma (road injuries, blunt objects wounds). For treatment, 129 (84.3%) cases visited a traditional healer; 81 (52.9%) cases visited a health facility and received Cloxacillin (n=78, 51%) and diclofenac (n=70, 45.8%). Ten (6.5%) cases were completely cured. Six/94 tested (6.4%) cases were HIV positive, 8 (8.5%) were syphilis positive, all referred for appropriate care. Dermohypodermatitis (n=14/28, 50%) and pyogenic granuloma (n=12/28, 43%) were the main anatomopathological findings. Mycobacterium ulcerans was absent. Socio-anthropological survey reported that Ladde’s origin as a diabolic disease caused by a spirit which comes from a demon-possessed animal or tree. Culex and Anopheles mosquitoes were identified. Phlebotomine vectors of leishmaniasis were not found.

CONCLUSIONS:
Post-traumatic leg ulcers with dermohypodermatitis were the predominant clinical pattern. Strengthening health and laboratory personnel capacity on chronic skin ulcers management could improve their outcome.