Dormant primary cutaneous actinomycosis: Acute exacerbation after 16 years

Summary Actinomycosis of head and neck are secondary to a nidus in the oral cavity and the aero-digestive tract. Primary actinomycosis without such predisposition is mostly due to trauma. We are presenting a case of this rare variant involving the forehead. The patient had a swelling over the forehead after a windscreen injury, which was asymptomatic for 17 years. However, 1 year ago, there was a repeat blunt trauma on the same site, but there was no breach of skin. Following this, the swelling became tender and started increasing in size. There was no response to a course of antibiotic and the patient had no concomitant history of any systemic illness. The swelling was excised and the biopsy revealed actinomycosis. This presentation of primary actinomycosis after such a long dormancy has never been reported before. This is yet another unusual presentation of actinomycosis, which is notoriously misdiagnosed owing to its rarity and numerous differential diagnoses.