Benign Paroxysmal Positional Vertigo (BPPV): This condition is characterized by brief, intense episodes of vertigo triggered by specific head movements, such as looking up. The symptoms described fit well with the typical presentation of BPPV, especially the positional nature of the dizziness.

Cervicogenic Dizziness: This refers to dizziness that originates from the cervical spine. Looking up can exacerbate cervical spine issues, leading to dizziness. The mechanism involves the stimulation of proprioceptors in the neck, which can affect balance.
Vestibular Migraine: Although vestibular migraines can cause a wide range of symptoms, some patients may experience vertigo or dizziness triggered by specific movements or positions, including looking up. The visual stimulation and movement could potentially trigger a migraine-related dizziness episode.

Vertebral Artery Dissection or Stroke: While less common, it's crucial to consider vascular causes of dizziness, especially if there are other symptoms such as headache, neck pain, or neurological deficits. Looking up could theoretically exacerbate a dissection by altering blood flow or putting additional stress on the vessel.
Multiple Sclerosis: In rare cases, multiple sclerosis can present with vertigo or dizziness, among other neurological symptoms. The symptoms can be triggered by certain movements or positions due to the demyelinating lesions affecting the brainstem or cerebellar pathways.

Chiari Malformation: This is a structural defect in the cerebellum that controls balance. Some patients with Chiari malformation may experience dizziness or vertigo, especially with certain head movements. However, this would be a less common cause of dizziness only when looking up.
Superior Canal Dehiscence: A rare condition where there is an abnormal opening in the bone overlying the superior canal of the inner ear. It can cause vertigo triggered by sound or pressure changes, and potentially by specific head movements, although this is less commonly reported.