Finding a bald patch on your dog is unsettling, and in India's warm, humid climate it is one of the most common reasons pet owners head to a vet. Unlike normal seasonal shedding, hair loss in clear patches almost always means a skin problem underneath that needs attention.
This guide covers the 6 most common causes of patchy hair loss in dogs, what each one looks like, which ones can spread to your family, and exactly when a bald patch means a vet visit.
What patchy hair loss usually means
Normal shedding is even, all over the coat, and leaves no bare skin. Hair loss in defined patches, with bald spots, scabs, redness, or a change in the skin, is different. It points to an underlying cause such as parasites, a fungal or bacterial infection, or an allergy. The location and the other signs (itching, smell, scabs) are the biggest clues to which one it is.
The quick rule: even, all-over shedding with healthy skin is usually normal. Defined bald patches with redness, scabs, a smell, or constant scratching need a vet to confirm the cause, because the right care is very different.
6 common causes of hair loss in patches
Mange (Sarcoptic or Demodectic) Urgent
Mange is caused by mites. Sarcoptic mange (scabies) is intensely itchy, spreads fast, and is contagious to other pets and people. Demodectic mange is less itchy and shows up as patchy hair loss, often on the face and around the eyes in young dogs. Street and rescue dogs in India are especially prone.
What to look for: intense scratching, bald patches with crusts and redness, thickened or darkened skin, and hair loss starting on the ears, elbows, or face. Sarcoptic mange can leave you with an itchy rash too.
What to do: see a vet promptly. Mange is confirmed with a simple skin scraping and needs vet-guided care to clear. Keep an affected dog away from other pets and wash bedding, since sarcoptic mange spreads easily.
Ringworm (Fungal, spreads to people) Monitor
Despite the name, ringworm is a fungal infection, not a worm. It produces round, scaly bald patches with broken hairs, often on the face, ears, and paws. It is common in India's humid months and is easily passed to humans and other pets by touch. Veterinary reviews of dermatophytosis in companion animals back this up: it is one of the most common skin infections that passes from pets to people, and young children and anyone with weaker immunity are most at risk.
What to look for: circular or oval bald patches, grey scaly or crusty skin, and broken stubbly hairs at the edges. It is often only mildly itchy, which is why it can spread before you notice.
What to do: see a vet to confirm it and start care, and wash your hands after handling your dog. Because it is contagious, act early to protect the rest of the household. Clean shared bedding and grooming tools.
Not sure if it is mange, ringworm, or an allergy?
PawCheck's skin scanner reads a photo of the affected patch and gives you a severity result, Normal, Monitor, or Urgent, in under 10 seconds.
Get it on Google Play ↗Flea Allergy Dermatitis Monitor
Many dogs are allergic to flea saliva, so even a few fleas trigger heavy itching and hair loss. In India's climate fleas are a year-round problem, not just a seasonal one. The classic pattern is hair loss and scabs over the lower back and the base of the tail.
What to look for: thinning hair and small scabs above the tail and along the back, constant biting or nibbling at the rear, and flea dirt (tiny black specks) in the coat. If the main sign is all-over itching, our guide on why dogs scratch so much in the monsoon goes deeper.
What to do: see a vet for a suitable flea-control plan and keep it up year-round in India. Use flea control on all pets in the home and wash bedding, since fleas live in the environment, not just on the dog.
Hot Spots (Moist Dermatitis) Monitor
A hot spot is a patch of skin that becomes red, wet, and painful very quickly, often within hours, as the dog licks or chews the area raw. Hair falls out over the spot. They flare in hot, humid weather and in thick-coated breeds, so India's monsoon is peak season.
What to look for: a well-defined moist, red, sometimes oozing patch, hair loss right over it, and a dog that keeps licking or chewing one spot. The area is usually sore to touch.
What to do: see a vet, and stop your dog worsening it (a cone helps). Hot spots can grow fast, so early care keeps a small patch from turning into a large painful sore.
Bacterial Skin Infection (Pyoderma) Monitor
Bacteria on the skin can multiply after scratching, an allergy, or a wound, leaving circular crusty bald patches that can look a lot like ringworm. It is often a secondary problem on top of another cause, which is why the underlying trigger also needs checking.
What to look for: round crusty or ring-shaped lesions, pimple-like bumps, a mild smell, and flaky skin. Often appears where the dog has been scratching or on skin folds.
What to do: see a vet, since pyoderma needs proper care and the root cause (allergy, parasites) should be found too. Do not use human antiseptic creams, some are harmful if licked.
Allergies or a Hormonal Cause Monitor
Food or environmental allergies cause chronic itching that leads to hair loss, often on the belly, paws, and around the eyes. Hormonal issues such as an underactive thyroid cause a different pattern: symmetrical thinning on both sides of the body with no itching. Both build up slowly over weeks.
What to look for: even thinning on both flanks (hormonal), or itchy paws, face, and belly with recurring infections (allergy). A dull coat, weight change, or low energy alongside hair loss points more to a hormonal cause.
What to do: see a vet, as these need proper work-up (diet trials or blood tests) to pin down. This is a slow, manageable problem, not an emergency, but it rarely resolves on its own.
When patchy hair loss means a vet, quick guide
- Same day: a large sore, wet, painful patch that is spreading fast, or hair loss with an open wound
- Within a few days: spreading bald patches, scabs, redness, a bad smell, constant scratching, or anything that could be contagious ringworm or mange
- Prompt visit: symmetrical thinning on both sides with a dull coat, weight change, or low energy (possible hormonal cause)
- Watch briefly: a single tiny thin spot on a comfortable dog with healthy skin, recheck in a few days
If the hair loss comes with other worrying signs, it helps to know the wider red flags. Our roundup of emergency warning signs in pets covers what should always mean an immediate vet visit.
Ringworm and sarcoptic mange can pass from dogs to people, especially children, through touch. If bald patches are spreading or anyone at home develops an itchy round rash, wash hands after contact and see a vet quickly. Never use human anti-fungal or steroid creams on your dog without a vet's advice.