Why Does My Dog Have Bald Spots? (Causes by Body Area)

Your dog has bald spots because something has interrupted the normal hair cycle — either hair is coming out faster than it grows in (scratched, chewed, licked or rubbed off) or the follicle itself has stopped producing it. Almost every case falls into one of six groups: parasites, allergies, skin infection, friction and pressure, hormonal change, or a breed-linked follicular pattern. Where the patch sits, whether your dog is itchy, and what the skin underneath looks like will narrow that list quickly.

A bald spot is a symptom, not a diagnosis — the real question is which process switched that follicle off, and answering it usually takes a skin scrape, tape cytology and a conversation with your veterinarian rather than a guess from a photo.

What interrupts a dog's hair cycle

Every hair follicle runs on a cycle: a growth phase, a transitional phase, and a resting phase before the hair is shed and replaced. Hair loss happens one of two ways. Either the coat is being physically removed — your dog is scratching, chewing or licking it off, or it is being abraded away by pressure — or the follicle has gone quiet and simply isn't pushing a new hair out. Self-trauma usually looks ragged, with broken hair stubble and reddened skin. Follicular shutdown usually looks clean: smooth, bare, often symmetrical skin with no inflammation at all.

The usual causes, in rough order of how often they turn up:

• Parasites. Fleas are the single most common trigger. Flea allergy dermatitis classically strips hair from the rump, tail base and the backs of the thighs. Sarcoptic mange is ferociously itchy and favours ear margins, elbows, hocks and the belly. Demodex mites, by contrast, often cause patchy loss with little or no itch, frequently around the eyes, muzzle and front legs in young dogs.
• Allergies. Environmental allergy (atopic dermatitis) and food allergy both drive hair loss indirectly — the dog itches, licks and chews, and the coat goes. The pattern tends to favour the face, ears, paws, armpits, groin and the flexural skin of the legs.
• Infection. Bacterial folliculitis produces circular, moth-eaten patches with scabs and flaky rings of peeling skin. Yeast overgrowth leaves greasy, musty, thickened, darkened skin in skin folds and between toes. Ringworm is a fungal infection, not a worm, and can produce scaly circular bald areas with surprisingly little itching — it also transmits to people, which is one reason a vet visit matters.
• Friction and pressure. Bony contact points take the brunt of hard floors. Elbows, hocks and hips develop thickened, hairless calluses, especially in large and heavy-coated dogs. Harnesses, collars and crate bedding can rub patches too.
• Hormonal and metabolic change. Hypothyroidism tends to cause symmetrical thinning over the trunk and tail with a dull coat, weight gain and heat-seeking behaviour, and typically no itch. Hyperadrenocorticism (Cushing's) can thin the coat over the body alongside thin skin, increased thirst and a pot-bellied look. These are diagnosed with bloodwork, not with shampoo.
• Follicular and breed patterns. Colour dilution alopecia in blue and fawn coats, pattern baldness in some short-coated breeds, recurrent flank alopecia in boxers and bulldogs, post-clipping alopecia in plush double coats, and localised bald patches at old wound, burn or injection sites.

A little sparseness is normal in some dogs — the thin triangles in front of the ears, a naturally bare belly, thinning ear flaps with age. A new patch that is spreading, scabbed, or bothering your dog is not normal.

Where the patch sits: a body map of hair loss

Location is the fastest triage tool you have.

Where the patch is	Most common explanations	What to look at
Back legs, thighs, hocks	Flea allergy dermatitis, sarcoptic mange, lick-driven loss over a sore joint, pressure callus on the hock	Flea dirt at the tail base; is the dog licking one spot repeatedly?
Elbows and other bony points	Pressure callus, hygroma, mange on the elbow margins	Is the skin thick and grey, or red and crusted? Floor surface and bedding
Sides and flanks	Hormonal disease, recurrent flank alopecia, post-clipping alopecia	Is it symmetrical on both sides? Any thirst, weight or energy changes?
Back and tail base	Fleas, bacterial folliculitis, hot spot after moisture or scratching	Part the coat and look for flea dirt, scabs, peeling rings
Head, around the eyes, ear margins	Demodex, ringworm, sarcoptic mange, rubbing from allergy	Scaling, crusts, head-shaking, face-rubbing on furniture
Muzzle and face folds	Yeast or bacterial infection in folds, contact rub from bowls	Odour, greasy feel, redness deep in the fold
Front legs and paws	Lick granuloma, allergy-driven chewing, demodex	A single wet, shiny, raised spot the dog returns to
Belly and groin	Allergy, yeast, hormonal thinning	Pink or spotted skin, bumps, pustules

Bald spots on the back legs and rump nearly always point at fleas first, even if you have never seen one. Patches on the sides and flanks that mirror each other tend to point away from itch and towards hormones or a follicular pattern. Elbow patches are usually mechanical — a dog that drops hard onto a tile floor several times a day will abrade the coat off that point. Bald spots on the head and face in a young dog raise demodex and ringworm high on the list, and both need a vet's microscope to confirm. Bald spots on the legs that your dog grooms obsessively usually mean something underneath is uncomfortable, itchy or painful.

Itchy, not itchy, or scabbed over

The itch question splits the differential almost in half.

Bald spots with itching mean the coat is coming off through trauma. Fleas, mites, allergies, bacterial infection and yeast all live here. Allergy-driven loss is rarely a single clean patch — it is diffuse thinning in the places a dog can reach, with pink skin, saliva staining on pale coats, and a dog that cannot settle in the evening.

Bald spots with no itching are the more telling finding. When a dog is not scratching at all and the skin looks calm, the follicle has usually stopped working rather than been damaged from outside. That points towards hypothyroidism, Cushing's, colour dilution alopecia, seasonal flank alopecia, post-clipping alopecia or scarring. This is the group most often missed at home, because nothing looks urgent — and it is exactly the group that needs bloodwork.

Bald spots with scabs or crusts mean the skin barrier is broken. Crusted, circular patches with peeling edges suggest bacterial folliculitis. Thick yellow crusts, oozing or a hot, painful area suggest a deeper infection or an acute moist dermatitis. Crusted ear margins and elbows raise sarcoptic mange. Scabs should move a vet visit up your calendar rather than down it, because topical products alone often will not resolve an established infection.

When sore joints show up as a bald patch

Two of the most commonly misread bald spots are orthopaedic in origin, not dermatologic.

The first is the licked patch. Dogs lick what hurts. A dog with a sore carpus, hock, stifle or elbow will groom that area until the hair is gone and the skin is shiny, thickened and sometimes ulcerated — a lick granuloma. Treating the skin alone rarely settles it, because the driver is underneath.

The second is the pressure point. A dog that is slow to get up, shifts weight off a limb, or lies down heavily instead of folding will grind the coat off its elbows and hocks. Hair loss there is a mobility signal as much as a skin signal.

This is where pawgen's work sits. K9-REPAIR is a BPC-157 and TB-500 peptide formulation made for dogs and dosed by body weight, built around joint, tendon and soft-tissue recovery rather than skin. BPC-157 is a peptide sequence studied for its role in tissue-repair signalling and blood vessel formation; TB-500 is related to thymosin beta-4, which research associates with cell migration and the actin remodelling involved in repair. These are emerging, promising areas of science, and they are why peptides have become the stack many owners run through a recovery period — not an FDA-approved veterinary drug, and not a claim about your dog's specific outcome. pawgen batch-tests and publishes certificates of analysis, which is more than can be said for the kitchen-sink joint chews that list twelve ingredients and disclose the amount of none of them. Talk to your veterinarian about where something like this fits alongside the pain plan, rehab or surgery they have recommended — it supports that plan, it never replaces it.

Do bald spots grow back?

Usually, yes. Dog hair regrows when two things are true: the follicle is still intact, and the cause has been dealt with. Flea control, allergy management, clearing an infection or treating an endocrine disease is typically followed by regrowth over weeks to months, depending on the dog, the coat type and the season. Double-coated breeds often fill in slowly and may come back a different texture or shade at first.

Hair does not regrow where the follicle has been destroyed. Deep burns, severe wounds, long-standing pressure calluses and scarred skin stay bare permanently. Colour dilution alopecia is progressive and managed rather than reversed. Recurrent flank alopecia often regrows on its own, sometimes on an annual rhythm.

What helps regrowth is unglamorous: a year-round parasite preventative, an accurate diagnosis, finishing the full course of anything prescribed, softer bedding for pressure points, and good nutrition. What does not help is cycling through shampoos and chews for months while the actual cause goes unidentified.

Key Takeaways

• Bald spots come from self-trauma (itch, lick, rub) or from follicles going quiet — the difference is usually visible in the skin.
• Location narrows it fast: rump and back legs point at fleas, symmetrical flanks at hormones, elbows at pressure, face in a young dog at mites or ringworm.
• Patches with no itching deserve bloodwork, not another shampoo.
• Scabs, crusts or odour signal infection and move the vet visit forward.
• Hair over an obsessively licked leg or a worn elbow is often a mobility problem wearing a skin disguise.
• Most hair regrows once the cause is addressed; scarred or callused skin may not.

Your veterinarian owns this one. A skin scrape, cytology, a fungal culture and basic bloodwork answer in a single visit what guesswork cannot answer in six weeks, and the diagnosis determines everything that follows. Supplements and peptides work in the space that proper veterinary care creates — they support a plan, they do not stand in for one, and nothing here is a reason to pause a prescription or delay a recommended procedure.

If you want to read further on pawgen's side of this, batch certificates of analysis for K9-REPAIR are published at /coas/, the full product range is at /shop/, shipping and availability details are at /location/, and K9-REPAIR itself — covered by a 60-day money-back guarantee and shipped direct to your door — is at pawgen.

Owners exploring peptide support for their dog can review K9-REPAIR — BPC-157 + TB-500 formulated for dogs — at https://pawgen.com/. BPC-157 and TB-500 are not FDA-approved veterinary drugs. Nothing in this article treats, cures or prevents any condition; every decision about your dog's care belongs with your veterinarian.