Benign Paroxysmal Positional Vertigo (BPPV): This condition is characterized by brief, intense episodes of vertigo triggered by specific head movements, which could explain the dizziness. The headache might be secondary to the vertigo, and the buzzing in one ear could be related to inner ear issues, although tinnitus is more commonly associated with Meniere's disease. BPPV is relatively common and can cause significant discomfort, making it a plausible initial consideration.

Meniere's Disease: This inner ear disorder is known for causing vertigo, tinnitus (which could be described as buzzing), hearing loss, and a feeling of fullness in the ear. The headache could be a secondary symptom due to the vertigo or tension. Meniere's disease is a common cause of vertigo and tinnitus, making it a likely consideration.
Migraine: Migraines can cause dizziness, headaches, and sometimes tinnitus or other auditory symptoms. The buzzing in the ear could be an aura symptom or part of the migraine itself. Given the prevalence of migraines and their varied presentations, this is a plausible diagnosis.
Labyrinthitis: An inner ear infection that can cause dizziness, hearing loss, and tinnitus. The headache could be part of the infection or a reaction to the vertigo. This condition directly affects the inner ear, which aligns with the symptoms described.

Stroke or Transient Ischemic Attack (TIA): Although less common, a stroke or TIA can present with sudden dizziness, headache, and sometimes tinnitus if the brainstem or cerebellum is involved. Given the potentially devastating consequences of missing a stroke, it must be considered, even if the symptoms seem atypical.
Acoustic Neuroma: A benign tumor on the nerve connecting the inner ear to the brain, which can cause tinnitus, hearing loss, and balance problems. While rare, missing this diagnosis could lead to significant morbidity due to tumor growth.
Multiple Sclerosis: This autoimmune disease can cause a wide range of neurological symptoms, including dizziness, headache, and tinnitus, especially if there are lesions in the brainstem or spinal cord. Early diagnosis is crucial for management.

Vestibular Neuritis: An inflammation of the vestibular nerve, which can cause sudden, severe vertigo, but it less commonly presents with tinnitus or headache as primary symptoms.
Superior Semicircular Canal Dehiscence: A rare condition where there's an abnormal opening in the bone overlying the superior semicircular canal, leading to vertigo and hearing symptoms, including autophony (hearing internal sounds unusually loudly) and possibly tinnitus.
Ototoxicity: Certain medications or substances can damage the ear, leading to hearing loss, tinnitus, and balance problems. This would be considered if the patient has been exposed to such substances.