Is Feline Hyperesthesia Syndrome "Kitty Fibromyalgia"?

Lots of Similarities

Feline hyperesthesia disorder has several things in common with fibromyalgia. John Lund/Getty Images

Question: I've heard of a disorder in cats that makes them hypersensitive to touch and makes them lash out at themselves or others. It's called feline hyperesthesia syndrome (FHS) and it sounds really similar to fibromyalgia. Is this condition basically kitty fibro?

Answer: While we can't say for certain – because FHS is even less understood than fibromyalgia – the two illnesses appear to have a few things in common.

First, some background. FHS is a rare condition in which a cat becomes sensitive to stimuli that shouldn't cause pain.

For example, you may reach down to give them a little scratch, which they'd usually like, only to have them run off with their back muscles twitching, making a horrible racket, and acting like they've just been zapped by a cattle prod.

Then, often, the cat will try to attack the site of pain. FHS is also called "rippling skin disorder" because of the distinctive way the skin and muscles on the cat's back move when the pain hits.

FHS has gotten a fair bit of publicity on the Animal Planet show My Cat from Hell. It had been a topic in earlier episodes, but in June 2014, a show aired that focused entirely on the cat that became famous (or possibly infamous) after his owners called 9-1-1 and said their cat had the whole family penned in a bedroom and wouldn't let them out. The story went viral and was carried by a lot of news shows nationwide.

On the show, the cat appears to be sweet and easy going except that, every now and then, he lays his ears back, yowls, and attacks anyone who comes near him. He's shown going through a series of veterinary appointments in which they find nothing wrong. Eventually, the vet diagnoses him with FHS and he's given treatment.

At the end of the episode, we find out that the treatment appears to be effective, as he hadn't been aggressive at all.

The show doesn't get into the specific medication(s) used, but FHS is often treated with anti-seizure drugs or SSRI antidepressants.

To anyone familiar with fibromyalgia, some similarities are obvious. Sensitivity to touch and pain-triggered mood/behavioral changes are part of both, and the two classes of drugs mentioned above are common in fibromyalgia as well.

On top of that, they're both diagnoses of exclusion, so you hear "nothing's wrong with you" over and over before being diagnosed. Hyperesthesia is similar to allodynia, which is a common pain type in us.

What we don't know is whether the mechanisms behind these illnesses are similar – primarily because we don't understand the mechanisms behind either of them. At their roots, they could be a lot alike or completely different.

The outward presentation, though, does seem to have a lot in common. Those of us with fibromyalgia don't tend to attack ourselves when the pain hits – if we did, we'd learn pretty quickly that it only increased the pain! However, who among us hasn't developed a sharp tongue and/or short temper when in the middle of a flare?

Both conditions can also involve depression and anxiety, too, and stress can set off symptoms.

So basically, you can say these two illnesses are similar in the same way that you can say two green trucks are similar when all you've done is look at them from the outside. But until you get a good look under the hood, you have no idea whether they've got, say, the same engine or transmission.

Regardless, the similarities are certainly strong enough to make you feel for a cat who experiences pain without knowing why.

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