Sometimes a cat will, to us, just start acting bonkers.
It can feel like their behavior is completely random and irrational. BUT… Cats are great at hiding their illnesses and weakness.
While, Hyperesthesia may not be a specific disorder but rather a sign of underlying medical or behavioral problems.
Most commonly, the skin along the lumbosacral area may twitch or ripple.
There may be excessive self-grooming, hissing or biting at the back or flank, and intensive tail wagging. Some cats cry, dash away, and even defecate. These episodes arise when the cat is highly aroused and may be incited by physical contact or external stimuli. A compulsive disorder is a consideration when the intensity, frequency, and duration of these problems is sufficiently severe.
Hypersthesia is frustrating as it can be very generic sounding “disease” and can manifest in so many different ways, makes it really frustrating when there is really nothing else to pinpoint what is going on with your cat. Sometimes cats will “see things”, get spooked and flee with hypersthesia (your quote above).
However, medical causes such as neuropathic pain, dermatologic conditions, myopathies, and focal seizures can also present with similar signs.
Therefore, a therapeutic response trial for neuropathic pain, seizures, pruritus, or compulsive disorders might be part of the diagnostic process.
Finding ways to relieve ALL stress from the cat as possible helps.