Bald patches on your cat: over-grooming, and what's driving it

A cat with a bald strip along the belly or the inside of the thighs has usually been licking it off for weeks. You didn't see it because cats groom when nobody's watching, at night, and because half of grooming looks like normal grooming until you count the minutes.

The default explanation offered — stress — is real but wildly over-applied. In referral dermatology caseloads, the substantial majority of cats presented for "psychogenic alopecia" turn out to have an underlying itch. Stress is a diagnosis of exclusion, and it should be reached last.

First: is the hair coming out, or being removed?

This single test redirects the entire investigation, and you can do it at home.

Look at the ends of the remaining hairs in the bald area, ideally with a phone camera zoomed in. Hairs that are blunt, broken, and stubbly — like a badly mown lawn — have been chewed off. That's self-trauma: the follicle is fine and the cat is removing the hair. Hairs that come away easily with tapered, intact tips, or skin that's genuinely smooth and hairless, points at a follicular or hormonal problem instead.

Second clue: hairballs and vomiting. A cat that has suddenly started producing more hairballs is swallowing more hair, which means more grooming. Owners often report the vomiting long before they notice the bald patch.

Third: the distribution. Cats over-groom what they can reach — belly, inner thighs, flanks, forelegs, base of the tail. Symmetrical loss in exactly those places is the signature of licking. Hair loss on the head or between the ears, where the tongue doesn't reach, is a different problem and often means scratching or a follicular disease.

The causes worth ruling out, in order

1. Fleas. Still first, still the most common, still worth treating properly even when you find nothing. Cats are efficient groomers and remove the evidence. Flea allergy dermatitis in cats classically causes miliary dermatitis — tiny scabs along the back and neck — along with over-grooming. Treat every animal in the house for at least three months before concluding it isn't fleas.

2. Other parasites. Cheyletiella, Demodex, Otodectes (ear mites, which can cause itching beyond the ears), and in outdoor cats, harvest mites. All are found on a skin scrape or flea comb, not by guesswork.

3. Environmental allergy. Feline atopic skin syndrome. Often seasonal at first, often accompanied by miliary dermatitis or ulcerated lesions on the lip or thigh.

4. Food sensitivity. Presents in cats as itching around the head and neck more often than elsewhere, frequently with GI signs. Needs a proper eight-week elimination trial, not a change of brand — the same protocol as in dogs applies, with the extra difficulty of separating cats at mealtimes.

5. Pain. Cats lick over what hurts. Focal licking over one hip, one flank, or the lower back is a common presentation of arthritis or bladder pain — a cat with cystitis will often over-groom the belly directly above the bladder. This one is missed constantly.

6. Stress and compulsive behaviour. Real, but reached only after the above. Typically triggered by a change: a new pet, a house move, building work, a cat visible outside, a change in the owner's schedule, conflict with another cat in the home.

What to track — and why the timeline is the diagnosis

Because the two big questions are when did this start and what changed, and both are answered by dates:

• Weekly photos of each affected area, taken from the same angle in the same light. Hair regrowth is slow and impossible to judge by eye across weeks. A photo strip settles it.
• Grooming episodes — roughly how long, and when. Evening and night-time clusters are typical of both itch and compulsive grooming.
• Hairball and vomiting frequency, counted.
• Food, everything, including treats. Non-negotiable if a diet trial is coming.
• Household events, with dates. New pet, guests, furniture moved, litter changed, holiday, builders.
• Flea treatment dates for every animal in the house.

PawSolids handles the photo timeline and the event log in the same place, per cat, which matters in a multi-cat house where you're trying to work out whose fur is missing and whether the flatmate's cat arriving in March is the date everything started. When you get to the dermatology appointment, the correlation view and a printed timeline do more for the diagnosis than any description you can give from memory.

Treatment follows the cause

There's no generic fix, which is precisely why the work-up matters. Parasites need parasiticides. Atopy needs allergy management. Food sensitivity needs a diet. Pain needs pain relief — and cats with arthritis-driven licking often stop within weeks of adequate analgesia.

For genuine compulsive grooming, the answer is environmental enrichment first: vertical space, predictable routine, separate resources for each cat in the home, structured play, and reduced conflict. Medication exists and helps some cats, but it's an adjunct to environment, not a substitute.

Book an appointment if: the skin is broken, ulcerated, or scabbed; there are raised, red, or ulcerated lesions on the lip or thigh; the hair loss is spreading quickly; your cat is also losing weight or drinking more; or the licking is focal and intense over one spot, which suggests pain underneath it.

The one thing not to do

Don't put a cone on and call it treated. Blocking the behaviour without addressing the cause leaves an itchy or painful cat that simply can't respond to it — and it removes the only signal you had.

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PawSolids is a health journal and pattern detector, not a diagnostic tool. Persistent over-grooming needs a veterinary work-up; the log is what makes that work-up short.