Paranasal sinus actinomycosis treated with a combination of surgery and long-term low-dose macrolide

Actinomycosis is a bacterial infection caused by actinomyces. Although almost 50% of cases are related to the head and neck region, those in the nose and paranasal sinuses (PNS) are rare. Actinomycosis of the PNS is presumed to be typically caused by dental caries, dental manipulation, and maxillofacial trauma, which facilitate the penetration of oral pathogens into the sinus, and should thus be treated by the combination of surgical removal and potent antibiotics for at least two months. The current use of these antibiotics might be redundant, considering the nature of actinomycosis of the PNS, which does not invade the mucosal surface. We herein report a 67-year-old female treated with endoscopic sinus surgery (ESS) and diagnosed with actinomycosis of the PNS by pathological findings. She had no history of dental impairment or treatment. She was given routine perioperative prophylactic antibiotics (cefazolin) during the surgery, followed by low-dose clarithromycin. The mucosa of the PNS normalized without any discharge by three months after the operation. The patient is a valuable example that should prompt reconsideration of the commonly accepted pathogenesis and treatment of actinomycosis of the PNS.