You notice it when you are stroking them on the sofa. A patch on the side where the fur is thin. A spot behind the ear that should be full but isn't. Maybe there's visible skin showing through. Your stomach drops a little — because this doesn't look like normal shedding. It looks like something is wrong.
It might be nothing serious. It might be something that needs a vet visit today. The difference between those two outcomes comes down to what else you are seeing alongside the patches — and that is exactly what this guide walks you through. Not to replace your vet, but so you go in knowing what you are dealing with and what questions to ask.
Read this now, while your dog is in front of you and you can actually check for the signs described here.
Quick Answer: Why Is My Dog Shedding in Patches?
Patchy shedding — where hair is being lost in specific areas rather than evenly across the body — is almost always a sign that something beyond normal seasonal shedding is happening. The most common causes are a skin infection (bacterial or fungal), mange, allergies causing the dog to scratch or chew specific areas, a hormonal condition like hypothyroidism or Cushing's disease, or a contact or environmental reaction. Normal shedding is even and all-over. Patchy, localised, or asymmetrical hair loss needs a vet to identify the cause — the sooner the better, because most causes are very treatable when caught early.
Table of Contents
- Normal shedding vs patchy hair loss: how to tell the difference
- What to check on your dog right now
- The most common causes of patchy shedding
- Mange: what it is and what to look for
- Ringworm: the fungal infection that causes bald circles
- Allergies and patchy shedding
- Hormonal causes: hypothyroidism and Cushing's disease
- Other causes worth knowing about
- What to tell your vet
- What happens at the vet
- FAQs
- Conclusion
- Related Posts
Normal Shedding vs Patchy Hair Loss: How to Tell the Difference
The single most important distinction is even versus localised. Normal shedding — including heavy seasonal blowouts in double-coated breeds — happens across the whole body. The coat may look thinner overall during a blowout, but it thins evenly. Patchy hair loss happens in specific spots: one side of the body, around the eyes, a circle on the flank, the base of the tail, along the back. That localisation is the signal that something is driving the hair loss in that specific area.
A second key distinction is what the skin underneath looks like. In normal shedding, the skin beneath the thinning coat is normal — healthy pink, smooth, no redness or flaking. In pathological hair loss, the skin underneath often tells the story: red and inflamed, flaky or scabby, darkened or thickened, greasy, or showing small pustules.
🔍 Normal Shedding vs Patchy Hair Loss — Key Differences
| Normal shedding | Patchy hair loss |
|---|---|
| Even across the whole body | Localised to specific areas or spots |
| Skin underneath looks normal and pink | Skin may be red, flaky, dark, greasy, or scabbed |
| Heavier in spring and autumn | Can appear at any time, not seasonally driven |
| Dog is not scratching the affected areas | Dog may be scratching, licking, or rubbing specific patches |
| Coat looks full elsewhere on the body | Coat may look moth-eaten or uneven across the body |
| No change in energy, appetite, or thirst | May accompany changes in behaviour or health |
If you are looking at your dog right now and what you see matches the right-hand column — keep reading. If you are seeing anything that concerns you, call your vet today rather than waiting to see if it resolves.
What to Check on Your Dog Right Now
Before anything else, do a hands-on check. Part the fur at the edges of the patchy area and look closely at the skin. You are looking for the following.
🔍 What to Look For at the Patch Site
- Is the skin red, inflamed, or warm to the touch? Suggests active infection or allergic reaction.
- Is there flaking or dandruff-like scaling? Can indicate fungal infection, seborrhoea, or mange.
- Are there small pustules, crusts, or scabs? Common in bacterial skin infections (pyoderma).
- Is the skin thickened, darkened, or leathery-looking? A sign of chronic inflammation, often from long-term allergies or hormonal conditions.
- Does the patch have a circular or ring-like border? Classic presentation of ringworm.
- Is there a smell coming from the skin? Yeasty, musty, or sour odour points to yeast overgrowth or bacterial infection.
- Is your dog scratching, licking, or rubbing that specific area? Self-trauma can drive and worsen patchy hair loss.
- Are there multiple patches, or just one? Multiple patches in different areas suggest a systemic cause rather than a local one.
Write down what you find. When you call the vet, this information helps them triage how urgent the appointment needs to be and gives them a head start before they see your dog.
The Most Common Causes of Patchy Shedding
There are several causes — some more serious than others, but almost all of them very treatable once correctly identified. The reason it matters to know which one you are dealing with is that the treatments are completely different. Treating a fungal infection with antibiotics does nothing. Treating mange with a shampoo designed for allergies does nothing. Your vet identifies the cause first; then the treatment follows.
Here are the most common causes, what they look like, and what to expect.
Mange: What It Is and What to Look For
Mange is a skin condition caused by mites — microscopic parasites that live in or on the skin. There are two types that affect dogs, and they behave quite differently.
Demodectic mange is caused by Demodex mites, which live in small numbers in the hair follicles of all dogs without causing problems. In puppies, young dogs, or dogs with weakened immune systems, the mites can multiply and cause patchy hair loss — typically starting around the face, eyes, and front legs. The skin in affected areas may look red and scaly but is often not intensely itchy in the early stages. Demodectic mange is not contagious to other dogs or humans. It often resolves on its own in mild cases in young dogs, but moderate to severe cases need treatment.
Sarcoptic mange (scabies) is caused by Sarcoptes mites, which burrow into the skin. It is intensely itchy — the dog will scratch relentlessly — and spreads rapidly to other dogs and can temporarily affect humans. Hair loss from sarcoptic mange tends to start at the ear margins, elbows, hocks, and belly. The skin becomes crusty and thickened. Sarcoptic mange needs prompt treatment.
Mange Needs a Vet Diagnosis — Don't Guess
Both types of mange are diagnosed by skin scraping at the vet — the mites are identified under a microscope. Sarcoptic mites in particular are notoriously difficult to find even on scraping. If your dog is intensely itchy and losing hair rapidly, treat it as a potential sarcoptic mange case until your vet says otherwise. It is also worth knowing that if you are experiencing unexplained itching yourself around the same time as your dog's symptoms, sarcoptic mange has likely transferred temporarily to you.
Ringworm: The Fungal Infection That Causes Bald Circles
Despite the name, ringworm has nothing to do with worms. It is a fungal infection — the same family of fungi that causes athlete's foot in humans — and it is one of the most recognisable causes of patchy hair loss in dogs because of the shape it produces.
Ringworm in dogs typically presents as roughly circular patches of hair loss with a scaly or crusty border. The hair at the edge of the patch often breaks off rather than falling cleanly from the root, giving the border a moth-eaten appearance. The skin inside the circle may be red, grey, or just bare. It most commonly appears on the face, ears, paws, and tail — but can appear anywhere.
Ringworm is highly contagious — to other dogs, cats, and humans. Children and immunocompromised adults are particularly vulnerable. If you suspect ringworm, limit the dog's contact with other animals and family members until you have a vet diagnosis, wash your hands after handling the dog, and avoid letting the dog sleep in beds or on upholstered furniture until treatment is underway.
📌 Ringworm Does Not Always Look Like a Perfect Circle
The classic ring shape is the textbook presentation, but ringworm in dogs frequently looks irregular, patchy, or diffuse — particularly in longer-coated breeds where the infection can spread before it becomes visible on the surface. If you are seeing any circular or roughly circular patch of hair loss with scaling or broken hairs at the edge, treat it as a possible ringworm case until your vet confirms otherwise.
Allergies and Patchy Shedding
Allergies do not directly cause hair loss — but they cause itching, and itching causes scratching, licking, and rubbing, which causes hair loss. The distinction matters because it means the patchy hair loss from allergies tends to appear in the specific areas your dog can reach: paws, inner thighs, belly, base of the tail, face, and armpits.
If you look at a patchy area on an allergic dog and the skin is red and irritated but relatively intact — and your dog is constantly working at that area — allergies are a strong candidate. The three main types are environmental allergies (grass, pollen, dust mites), food allergies, and contact allergies (reactions to something the skin has direct contact with, like a new bed or a cleaning product).
Secondary Infections Make Allergy Shedding Worse
Dogs who scratch and lick repeatedly at the same area break the skin barrier, which allows bacterial and yeast infections to take hold. Those secondary infections then drive more itching and more hair loss. This is why allergic dogs often end up with both an allergy problem and an infection problem at the same time — and why treating only one without the other rarely gives lasting results. Your vet will often treat the infection first to get the skin stable, then address the underlying allergy.
Recommended
Veterinary Formula Clinical Care Antiseptic & Antifungal Shampoo
If your vet has confirmed a bacterial or yeast skin infection alongside the patchy hair loss, a medicated shampoo is often part of the treatment protocol. This one covers both bacterial and fungal causes, is gentle enough for regular use on sensitive skin, and gives real relief from the itching that drives self-trauma and worsens the patches. Always use it as directed by your vet alongside any prescribed medication — not as a replacement for diagnosis and treatment.
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Hormonal Causes: Hypothyroidism and Cushing's Disease
Two of the most common hormonal conditions in dogs — hypothyroidism and Cushing's disease — both present with hair loss as one of their main visible signs. The hair loss in both conditions tends to be symmetrical and bilateral, meaning it appears on both sides of the body in mirror-image patches, particularly on the flanks, trunk, and tail. The dog is typically not itchy.
Hypothyroidism occurs when the thyroid gland underproduces thyroid hormone, slowing the body's metabolism. Alongside patchy hair loss, you may notice weight gain without a change in diet, lethargy, cold intolerance, and a coat that looks dull and feels dry. It is one of the most common endocrine disorders in dogs and is very manageable with daily medication once diagnosed.
Cushing's disease (hyperadrenocorticism) occurs when the body produces too much cortisol, either from a pituitary or adrenal tumour. The coat changes are similar — symmetrical hair loss on the trunk — but Cushing's has additional distinctive signs: a pot-bellied appearance, increased thirst and urination, increased appetite, and skin that becomes thin, wrinkled, and prone to bruising. If your dog is also drinking and urinating much more than usual alongside the patchy hair loss, Cushing's is high on the list of possibilities and your vet needs to know about those symptoms.
Hormonal Hair Loss Is Not Itchy
This is one of the most useful distinguishing features. If your dog has symmetrical patchy hair loss and is not scratching at it — the patches are just there, not bothering them — a hormonal cause is more likely than an infection or allergy. That does not mean you can manage it at home. Both conditions need blood testing to confirm and ongoing treatment to manage. But knowing this distinction helps you describe what you are seeing accurately to your vet and helps them prioritise which tests to run first.
Other Causes Worth Knowing About
Alopecia X — sometimes called black skin disease — is a poorly understood cosmetic condition seen mostly in Nordic breeds (Pomeranians, Huskies, Samoyeds, Malamutes) and some other breeds. It causes symmetrical hair loss on the trunk and tail with no other symptoms and no identified underlying cause. The skin may darken. The dog is otherwise completely healthy. It is frustrating because there is no reliable treatment, but it is cosmetic rather than medical — it does not affect quality of life.
Post-clipping alopecia affects some double-coated dogs after shaving — the coat grows back slowly, unevenly, or not at all in the clipped area. This is one reason shaving double-coated breeds is strongly discouraged. If your dog was recently shaved and the coat is not growing back normally, mention this to your vet.
Stress and telogen effluvium — significant physical or emotional stress (whelping, illness, surgery, a major change in environment) can trigger a temporary wave of hair loss several weeks after the stressor. The hair loss is typically diffuse and all-over rather than patchy, and the coat usually recovers fully once the dog is stable.
Flea allergy dermatitis is worth mentioning separately from general allergies because it is so common and so specifically located. A flea allergy reaction causes intense itching and hair loss concentrated at the base of the tail, lower back, inner thighs, and belly — the areas fleas prefer. Even one or two flea bites in a sensitised dog can trigger a weeks-long reaction. If the patchy hair loss is concentrated in that lower-back-to-tail region and your dog is scratching relentlessly there, check thoroughly for fleas and flea dirt before your vet appointment.
What to Tell Your Vet
The more information you can give your vet before they examine your dog, the faster they can reach the right diagnosis. Here is what to note down before you call or go in.
Information to Have Ready for Your Vet
- When did you first notice the patch? A week ago, a month ago, gradually over several months?
- Has it grown, stayed the same, or appeared in new places? Spreading patches suggest a different cause than a single stable one.
- What does the skin at the patch look like? Red, flaky, crusty, darkened, normal? Use your notes from the check you did earlier.
- Is your dog scratching, licking, or rubbing at it? Or does it seem not to bother them at all?
- Any changes in thirst, urination, appetite, energy, or weight? These systemic signs point toward hormonal causes.
- Has anything changed recently? New food, new washing powder, new bed, new garden, new pet in the house, recent illness, recent medication.
- Are other pets in the household affected? Ringworm and sarcoptic mange spread between animals.
- Is any human in the household experiencing unexplained itching? Relevant for sarcoptic mange and ringworm.
- What is your dog's flea and parasite prevention, and is it up to date? Your vet will ask.
What Happens at the Vet
Knowing what to expect makes the appointment less stressful — for you and your dog. Your vet will do a physical examination of the affected area and likely run one or more of the following, depending on what they find.
A skin scraping involves gently scraping cells from the surface of the skin onto a slide for microscopic examination. This is how mange mites are identified. It is quick and causes minimal discomfort.
A Wood's lamp examination is a UV light that causes some strains of ringworm fungi to fluoresce green. It is not definitive — not all ringworm strains fluoresce — but it is a fast first step.
A fungal culture involves taking hair and skin samples and culturing them on a growth medium. It definitively confirms or rules out ringworm, but results take one to three weeks.
Blood tests are used to check thyroid levels and run a full panel to look for signs of Cushing's disease or other systemic causes. If your vet suspects a hormonal cause based on the pattern of hair loss and any accompanying symptoms, blood work will be part of the workup.
A skin biopsy is occasionally needed for cases that don't respond to initial treatment or where the diagnosis is unclear. A small sample of skin is taken under local anaesthetic and sent to a laboratory for histopathology.
The most important thing you can do is go in rather than wait and see. Most of the conditions that cause patchy hair loss in dogs are straightforward to treat once correctly identified — and the longer an infection, infestation, or hormonal condition goes unaddressed, the harder it becomes to get the skin fully back to normal.
Recommended
Zymox Enzymatic Ear & Skin Care Kit
Yeast and bacterial overgrowth on the skin — both common secondary infections in dogs with allergies or compromised skin barriers — respond well to enzymatic treatment between vet visits. This kit covers topical skin care and ear care, which often go together in dogs with allergy-related patchy hair loss. Use it as a supportive treatment alongside whatever your vet has prescribed, not as a substitute for the vet visit itself. Worth having in the cupboard once you know your dog has skin sensitivities.
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Frequently Asked Questions
Is patchy shedding always something serious?
Not always — but it is always worth investigating. Some causes, like a mild localised hot spot or early flea allergy, are straightforward to treat. Others, like mange or hormonal conditions, need prompt diagnosis and ongoing management. The pattern of the patches, what the skin underneath looks like, and whether your dog is itchy or showing any other symptoms together give a much clearer picture. When in doubt, call your vet rather than waiting to see if it resolves on its own — most causes of patchy hair loss do not resolve without treatment.
My dog is losing fur in a circle — is it ringworm?
A roughly circular patch of hair loss with a scaly or crusted border is a classic presentation of ringworm, and if that is what you are seeing, treat it as a probable ringworm case until your vet confirms otherwise. Limit contact between your dog and other pets and family members, wash your hands after touching the area, and get a vet appointment promptly — ringworm spreads quickly between animals and to humans, particularly children. That said, not all circular patches are ringworm, and not all ringworm looks circular. Your vet confirms it with a culture or lamp examination.
Could stress cause my dog to shed in patches?
Stress can cause a temporary wave of increased shedding — called telogen effluvium — that sometimes appears patchy. It typically follows a significant stressor a few weeks prior: a house move, the loss of another pet, a serious illness, or whelping. The hair loss is usually more diffuse than distinctly patchy, and the coat generally recovers once the dog is settled. If the patches have a distinct edge, the skin underneath looks abnormal, or your dog is scratching at them, the cause is more likely physical than stress-related.
Can I treat patchy shedding at home without going to the vet?
Honestly — no, not effectively, and it can make things worse. The causes of patchy hair loss require different treatments, and using the wrong one delays recovery and can mask symptoms that help your vet reach the right diagnosis faster. A medicated shampoo for infections used on a hormonal hair loss case does nothing. An anti-itch treatment for allergies used on mange leaves the mites untreated and allows the infestation to spread. The vet visit is not optional here — it is what makes the treatment work.
My dog has patches around their eyes and muzzle. What is that?
Patchy hair loss around the face — particularly around the eyes, muzzle, and front legs — in a young dog is a classic early presentation of demodectic mange. In an older dog, it can also indicate an immune-related condition or a localised skin infection. It warrants a vet visit. Demodectic mange in young dogs often resolves with treatment and sometimes even on its own as the immune system matures, but moderate or spreading cases need prescription treatment.
Will the hair grow back?
In most cases, yes — once the underlying cause is treated and the skin heals, the hair follicles recover and regrowth begins. The timeline varies by cause: bacterial infections may show regrowth within a few weeks of treatment, while hormonal conditions may take several months after the hormone levels are stabilised. In some cases — severe long-term infections, post-clipping alopecia in double-coated breeds, and some cases of alopecia X — regrowth can be partial or slow. Your vet can give you a realistic expectation for your dog's specific situation once the cause is confirmed.
Conclusion
Finding a patchy bald spot on your dog is one of those moments that puts you on high alert as a dog parent — and honestly, that instinct is right. Patchy hair loss is your dog's skin telling you something is happening that needs attention. It is rarely an emergency, but it is also rarely something that resolves on its own without identifying and addressing the cause.
The good news is that the most common causes — mange, ringworm, allergies, bacterial or yeast infections, and hormonal conditions — are all very treatable. Dogs who are diagnosed promptly and treated correctly get their coats back. The ones who wait six months while the owner tries various shampoos are the ones with more extensive skin damage and longer recovery times.
So do the check described in this guide, note down what you find, call your vet, and go in. Your dog cannot tell you what is wrong. The patchy fur is the closest thing they have to pointing at it.
Has your dog had patchy hair loss and been diagnosed with something specific? What was the cause and how did treatment go? Share in the comments — the more experiences are on here, the more useful this page is for the next dog parent who finds a patch and starts searching at midnight wondering what it means.
Related Posts
- Dog Shedding Solutions That Actually Work — If the patchy hair loss has been ruled out as medical and your dog is just a heavy shedder, this is the complete guide to getting the volume under control — right tools, right technique, right routine.
- How to Reduce Dog Shedding Fast — The immediate fixes that make a real visible difference the same day, from a deshedding bath done properly to the rubber glove trick that beats every lint roller on the market.
- Dog Skin Problems: A Guide for Dog Parents — A broader look at common skin conditions in dogs — what they look like, what causes them, and when the grooming aisle stops being the answer and the vet needs to step in.
- Dog First Aid Kit Essentials: Everything You Need at Home — The things worth having before you need them — including what to use for skin irritation, hot spots, and minor wound care while you wait for a vet appointment.
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