Health
Tufts on the sofa are one thing. Round patches, bald flanks or a dog scratching himself raw are something else. Here is how to tell them apart.
Caution. Red skin that weeps or spreads from hour to hour, a heavy smell, a dog who cannot sleep for itching, bald patches on the dog plus round spots on someone's skin at home, or hair loss with a big thirst and lethargy: see your own vet the same day.
Do not look for the answer in a Facebook group, on TikTok or on a forum. Look for someone trained for this: your dog's own veterinarian, the only person who can examine, investigate and treat them.
Use this page to know what to observe, what to note and what to ask at the appointment, not to treat at home. If you still have doubts after a consultation, ask another vet or a specialist (dermatologist, internist) for a second opinion, not a group. And if you do not have a regular vet yet, find one now, while your dog is healthy: how to choose a veterinary clinic.
Three dogs, three different stories. The labrador leaves tufts all over the sofa from March to May, and this year it feels worse than ever. The three-year-old crossbreed has a round bald patch the size of a thumbnail on one front leg, and another on his head. The eight-year-old has gone bald on both flanks, a mirror image left and right, never scratches, and has lately been drinking more. The first one is almost certainly fine. The other two need to see a vet. Below is how to tell them apart, what to write down and what your own vet will be looking for when you bring in a dog who is losing hair.
Losing hair is not an emergency on its own. What comes with it can be:
If nothing on that list fits, you have time to watch for a few days and go in with decent notes.
Before any test, your vet will want three things: where the hair is coming out, whether he is itchy and what the skin underneath looks like. You can gather all three yourself.
The map. On a sheet of paper, sketch the dog from the left, from the right and from above, and shade in the bald or thin areas. Is it the same on both sides of the body or the flanks? Round patches scattered about? Only the head and legs? Only where his mouth can reach, or only round the tail? Date the sheet and draw it again in two weeks.
The itch. Score it from nought to ten: nought is a dog who never touches himself, ten is the one who stops mid-walk to scratch. A dog losing hair without itching falls into one group. A dog who scratches first and loses hair afterwards falls into a completely different one, with different tests.
The skin. Part the coat in good light. It might be normal (pale pink or evenly pigmented, smooth), or red, with spots or little bumps, with rings that peel at the edge, thickened and dark like elephant hide, dry, flaky, greasy to the touch, crusty. Take close-ups of each area with the flash on.
The hair. Is it coming out root and all, or snapped off short as if clipped? Tug gently on a tuft at the edge of a patch. If it comes away whole with no effort, write that down. With an ordinary moult the hair comes evenly from everywhere, the skin looks healthy and nothing is left bare.
The history. His last flea and tick treatment (product and date; a photo of the box does the job). His food and any change in recent months. Whether he has been ill, had surgery or an anaesthetic in the last three months, whether she has had a litter, whether he was clipped short recently or you changed shampoo, whether he is neutered. Whether there are other animals at home, and whether anyone in the family is itchy.
Behaviour. Does he keep licking one spot, usually on a front leg, when he is left alone or bored? The shiny bald patch you get there often comes from pain or boredom, and the skin itself was never the problem.
| What it looks like | Itchy? | Common causes |
|---|---|---|
| Thinning all over, even, healthy skin, in spring or autumn | No | Normal moult, heavier in breeds with a dense undercoat and in dogs living in centrally heated homes |
| Symmetrical on flanks and body, thin or darkened skin, a "tired" dog | No | Underactive thyroid, too much cortisol, sex hormone imbalance |
| Round patches with peeling edges; sometimes on people at home too | Little or none | Ringworm (a fungus), sometimes a bacterial infection of the follicles |
| Patches on the head, round the eyes, on the legs, in a puppy or young dog | None or a little | Demodex mites, which live in the follicles |
| Ear edges, elbows, hocks, belly, ferocious itching | Severe | Sarcoptic mange, highly contagious, can pass to people |
| Base of the tail and the back, small crusts, chewed areas | Marked | Flea bite allergy |
| Paws, face, ears, armpits, itch that comes back each season or lasts all year | Marked | Environmental or food allergy, often with infections on top |
| Hair dropping out in tufts 1 to 3 months after an illness, a litter or an anaesthetic | No | The follicles "reset"; the coat grows back by itself |
| A patch still bald long after clipping, in Nordic breeds or Pomeranians | No | Hair growth stalls after clipping, a problem specific to these breeds |
| One shiny patch on a front leg, licked constantly | Licking, not scratching | Pain in the joint underneath, or a habit grown out of boredom and stress |
No table replaces the scrape and the microscope. Plenty of causes look alike, and one dog can have two at once, for example an allergy with a bacterial infection settled on top.
Brushing that suits his coat. In the moulting season that means every day, with a metal-toothed undercoat rake; a blade that cuts the hair is the wrong tool. Flea protection all year round, because one flea is enough for an allergic dog. A complete food with good fats, not swapped on a whim. Baths only when he really needs one, with a dog shampoo, rinsed well and dried right down to the skin. Once a month, while you are brushing him anyway, have a look underneath the coat. A patch the size of a button is a routine appointment. One the size of your palm means you have already lost a month.
If the hair comes out evenly, the skin is healthy and the dog is happy, it is most likely just the time of year. Patches, changed skin, or a dog whose behaviour has changed as well mean the notes above and a trip to the practice. If you do not have a regular vet yet, our related services page explains how to choose one.
What dog owners search for most often on the internet about this problem, with the short answer. The answers are a guide only: the decision belongs to your dog's own vet, after an examination.
If the hair comes out evenly, the skin is healthy and it is spring or autumn, he is moulting. If bare areas are left, the usual causes are parasites (fleas, mites), ringworm, allergies with scratching, bacterial infections of the follicles and, in dogs who do not scratch, hormonal disease. Where the patches are and whether he is itchy tell your vet where to look.
Alopecia means hair missing where it should be, in patches or all over. It is a sign, and treatment goes after whatever cause is found: the parasite, the fungus, the infection, the allergy or the hormone imbalance. That is why your vet scrapes the skin, looks under the microscope and, for symmetrical loss without itching, runs bloods before treating anything.
In breeds with a dense undercoat (labrador, husky, German shepherd), two big moults a year and hair around the house all year are normal, especially in dogs living in warm homes under artificial light. It is not normal for bare spots to stay, for the skin to be red or flaky, for him to scratch, or for hair to come away in tufts at the lightest touch. Daily brushing in season deals with the normal part.
We would not. The undercoat protects him from cold and sun, and in some breeds (Nordic breeds, Pomeranians) a shaved coat does not grow back the same for months or even years. Bare skin burns, and the shedding does not drop; the hairs are simply shorter. An undercoat rake used daily in season pulls out more hair than any clip and leaves the coat intact.
It could be, especially if the edges peel and someone at home has round red spots on their skin. But round patches also come from Demodex mites, bacterial infections of the follicles and some injections. Your vet tells them apart with a lamp, a skin scrape and a culture that takes up to three weeks. Until then, wash your hands after touching him and keep children away from the patches.
The information on this page is educational and does not replace an examination. For full details and a diagnosis, consult your dog's own veterinarian.
They often come together: the same causes, plans that complement each other.
Claws on the belly at midnight, paws licked red, an ear infection every summer. Behind the word "allergy" sit at least three diseases, each with its own plan.
A hard bead with legs on his neck after the woods, or black specks on the sofa that turn red when wet. Both can be sorted out, and neither with oil or garlic.
The wet slurping every evening, rusty paws, a bald patch on the wrist. Licking is a symptom, and "he's bored" is the diagnosis that comes last, not first.
Something soft under the skin, a pink button on the eyelid, a swelling that has grown since Easter. You cannot identify any of them by touch. The needle can.
We work with your dog's behaviour, not its health. For any sign described here, book an appointment with your own vet; the related services page explains how to choose a clinic.