Feline Hyperesthesia Syndrome (FHS) in Cats

Causes, Treatment, and Prevention

Grey Cat bends his back
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Feline Hyperesthesia Syndrome (FHS), commonly called rippling skin disorder, can be mistaken for normal crazy behavior in cats. However, it's a neurological syndrome that may require treatment. Tuning in to the symptoms, such as skin twitching, abnormal vocalizations, and erratic behavior will help you and your veterinarian identify the need for medical intervention.

What Is Feline Hyperesthesia Syndrome?

Feline Hyperesthesia Syndrome (FHS) is a neurological disorder in which the characteristic neurological symptom is rippling or shuddering skin (particularly on the back, near the base of the tail). FHS also manifests as behavioral abnormalities that are even more concerning, such as anxiety and generalized agitation.

Symptoms of Feline Hyperesthesia Syndrome

To track symptoms that may indicate Feline Hyperesthesia Syndrome, consider keeping notes on a calendar, documenting the frequency of twitching or odd behaviors, such as those listed below.


  • Involuntarily rippling or twitching of the skin, particularly on the lower back, accompanied by biting and scratching at the affected area
  • Loud and insistent meowing (often at night)
  • Dilated pupils, glassy eyes
  • Erratic racing in circles or back and forth
  • Extreme sensitivity and discomfort from petting or any physical contact
  • Seizures

The symptoms of the disorder all point to a common neurological cause that elicits hypersensitivity externally (in the skin) as well as internally, creating anxious behaviors of restlessness and agitation that can not be easily soothed with affection. Although seizures are a rare symptom of FHS, they can indicate a serious underlying condition involving the brain.

Causes of Feline Hyperesthesia Syndrome

Feline Hyperesthesia Syndrome can be caused by a health condition or environmental exposure to a neurological disruptor. While any cat can be affected by it, Asian breeds such as the SiameseBurmeseAbyssinian, and Persian tend to be diagnosed more frequently. Most cats affected by Feline Hyperesthesia Syndrome start to exhibit symptoms between one and five years of age. Possible triggers include:

  • Pansteatitis: This condition, caused by an excess of unsaturated fatty acids from a high-fish or imbalanced homemade diet, causes abnormal fatty deposits under a cat's skin that can be painful. The uncomfortable fatty deposits create hypersensitivity in the thorax and abdomen, and a cat's skin may twitch or ripple as a result.
  • Brain Involvement: If a cat with FHS experiences seizures, the cause may stem from the brain. Infection, skull trauma, or tumors should be investigated by a veterinarian.
  • Toxic exposure: Environmental or dietary heavy metals such as arsenic or mercury-containing foods or compounds can cause FHS. Flea dips, flea collars, or the ingestion of household cleaning agents and pesticides should also be considered.
  • Flea Allergies: Itchy skin due to flea bites could be cause for erratic behavior in cats, and this potential cause should be relatively easy to rule out by examination of the skin under the coat.

If all of the above causes have been ruled out, Feline Hyperesthesia Syndrome will most likely be attributed to OCD (Obsessive-Compulsive Disorder) or as an undefinable stress-related condition.

Diagnosing Feline Hyperesthesia Syndrome in Cats

Diagnosis of FHS is often a process of elimination. If no external stimuli or toxic exposure can be identified, then a veterinarian will look to causes such as diet (abnormal fat consumption and deposition) or trauma. Because this condition is so often idiopathic (no known cause), your doctor may recommend dietary modifications to optimize weight and nutrition as well as the removal of environmental stressors to address FHS before opting for more diagnostic tests like x-rays. Of course, if seizures have been noted, then further tests may be required.

Treatment and Prevention

A cat with FSH can be helped at home by relieving stressors along with providing exercise-based activities, such as interactive play with wand toys. Clicker training, a very effective and fun behavioral modification approach, may be used to stimulate a cat's activity level and alleviate anxiety.

Removing negative influences and exposures, such as other aggressive pets or loud noises, can help. A diet change to maximize nutrition and encourage weight loss (if necessary) is also a viable treatment strategy.

Anti-convulsant medication, such as phenobarbital, may occasionally be prescribed for the FSH cat that experiences seizures, or low dosages of mood-stabilizing drugs may be prescribed to help calm a cat.

Although a cat with Feline Hyperesthesia Syndrome may never be entirely "cured" with modifications or medication, you can work with a pet behaviorist to help your cat feel happier and more comfortable.

Prognosis for a Cat with Feline Hyperesthesia Syndrome

The outlook for a cat with FHS depends on the cause of the condition. In most cases, diet or environmental changes can help a cat feel more relaxed. Toxic exposures can cause lasting neurological damage, but many cats can recover once it is no longer in contact with the chemical. Brain problems carry a more guarded prognosis depending on the type and severity of the issue.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
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  1. Amengual Batle, Pablo et al. Feline Hyperaesthesia Syndrome With Self-Trauma To The Tail: Retrospective Study Of Seven Cases And Proposal For An Integrated Multidisciplinary Diagnostic ApproachJournal Of Feline Medicine And Surgery, vol 21, no. 2, 2018, pp. 178-185. SAGE Publications, doi:10.1177/1098612x18764246

  2. Hyperesthesia Syndrome. Cornell University College Of Veterinary Medicine.