RESUMEN
Actinomycosis is a rare, chronic bacterial infection caused by Actinomyces species, characterized by granulomatous inflammation, abscesses, and sinus tracts. It primarily affects the cervicofacial region and often mimics other conditions such as malignancies or tuberculosis, complicating early diagnosis and treatment. This case report details an 18-year-old male with no known comorbidities, who presented with a two-week history of facial swelling, trismus, and discharging fistulas following an insect bite. The delay in seeking medical attention was due to initial symptom subsidence and challenges in accessing care. Diagnostic difficulties arose from inconclusive pus cultures and the lack of specialist resources at our facility. An incisional biopsy and subsequent histopathological examination revealed basophilic Gram-positive, non-acid fast filamentous bacteria and the Splendore-Hoeppli phenomenon, ultimately confirming actinomycosis. This case highlights the necessity of including actinomycosis in the differential diagnosis of facial infections and demonstrates the value of a multidisciplinary approach in managing complex cases with diagnostic and therapeutic challenges.