Bezold's Abscess Secondary to a Subclinical Mastoid Infection: Diagnostic Challenges and Literature Review.

Bezold's abscess is a rare but serious extracranial complication of otitis media, typically resulting from erosion of the mastoid tip. We report the case of a 34-year-old male with a two-month history of recurrent right-sided otalgia, occurring two to three times and each treated with short courses of oral antibiotics, without any ear discharge, who presented with a progressively enlarging, painful, right cervical swelling and low-grade fever. The recurrent mild otologic symptoms, likely the result of repeated antibiotic exposure, delayed recognition of the more serious underlying mastoiditis. Imaging revealed erosion of the mastoid tip and opacification of the mastoid air cells. According to the clinical and radiological findings, the condition was consistent with masked mastoiditis, a subclinical mastoid infection in which inflammation remains confined to the mastoid cavity due to blockage of the aditus ad antrum, often following partial suppression of acute symptoms by antibiotics. The absence of tympanic membrane perforation or obvious otorrhea further delayed recognition until complications developed. Surgical drainage and mastoidectomy were curative. Notably, this episode also led to the incidental discovery of previously undiagnosed diabetes mellitus, highlighting the role of impaired host immunity in disease progression. This case underscores the diagnostic challenges of masked mastoiditis and illustrates the need to consider it as an underlying pathology in unexplained deep neck infections.