By Dial A Vet Veterinary Team
Finding clumps of fur on the couch is normal for many dogs. Finding bald patches, broken hairs and a dog who will not stop scratching is not. When itching and hair loss happen together, it usually means the skin itself is inflamed, and the hair is either being scratched out or falling out because the follicles are unhealthy. Sorting out which is happening, and why, is the job of a vet examination. Here is what they will be thinking about.
Key takeaways
- Itching with hair loss most often comes from parasites, allergies or skin infections.
- Fleas and flea allergy are the most common cause in Australia, even if you never see a flea.
- Sarcoptic mange causes intense itch and hair loss on ear edges, elbows and belly, and is contagious.
- Hair loss without much itch can point to hormonal disease, demodectic mange or ringworm.
- Persistent or spreading hair loss needs a vet check.
Normal shedding or a problem?
Shedding is a normal part of the hair cycle, and many breeds blow their coat seasonally. Normal shedding is even across the body, the skin underneath looks healthy, and there are no bald patches. Signs of a problem include:
- Patchy or symmetrical bald areas
- Broken or chewed hairs
- Red, scaly, crusty or darkened skin
- Odour, greasiness or discharge
- Constant scratching, licking or chewing
Common causes
Fleas and flea allergy
In flea-allergic dogs, a few bites cause intense itch, especially around the lower back, tail base and back legs, leading to hair loss and scabs. Year-round flea control for every pet in the house is the first step.
Sarcoptic mange
The Sarcoptes mite burrows into the skin and causes extreme itch, with hair loss and crusts on the ear edges, elbows, hocks and belly. It is contagious to other dogs and can cause a temporary rash in people. In Australia, foxes and wombats can carry it.
Demodectic mange
Demodex mites live in hair follicles. When numbers grow out of control, patchy hair loss develops, often around the eyes, face and front legs. Itch is usually mild unless infection sets in. See our article on Demodex mites in dogs.
Environmental and food allergies
Allergic dogs lick and chew their paws, face, armpits and belly, causing hair thinning and saliva staining, and often have recurrent ear infections.
Bacterial and yeast infections
Infections cause circular patches of hair loss with crusty edges, pustules, odour and greasy skin. They are usually secondary to allergies or other skin problems.
Ringworm
A fungal infection that causes round patches of hair loss with scaling. It is often only mildly itchy and can spread to people and other pets. See ringworm in dogs.
Hot spots
Sudden, wet, painful patches where the dog has licked and scratched the hair away.
Hormonal disease
Hypothyroidism and Cushing's disease often cause symmetrical hair loss on the body and tail with little itch at first, but secondary infections can add itch. Other signs include weight change, lethargy, increased thirst or a pot-bellied appearance. Read about Cushing's disease in dogs.
Contact irritation and other causes
Plants, chemicals, shampoos, stress-related licking and, uncommonly, autoimmune disease or skin cancer can also cause itch and hair loss.
What the pattern can suggest
- Lower back and tail base: fleas
- Ear edges, elbows, hocks, intense itch: sarcoptic mange
- Around eyes and face in a young dog: demodectic mange
- Paws, face, armpits, belly: allergies
- Round, scaly patches: ringworm or bacterial infection
- Symmetrical on the body, little itch: hormonal disease
These are clues, not a diagnosis. Many dogs have more than one problem at once.
When to see a vet
Same day: raw, bleeding or oozing skin, rapidly spreading patches, a very itchy dog who cannot rest, or a dog who is unwell, not eating or has a fever.
Within a few days: any patchy hair loss, hair loss with itch lasting more than a week, or hair loss along with weight change or increased thirst.
Also see your vet if family members develop itchy red spots or round skin patches.
What you can do in the meantime
- Check for fleas and flea dirt, and make sure all pets are on effective flea control.
- Stop your dog licking or chewing with a cone or T-shirt.
- Take photos to track any changes.
- Wash bedding in hot water.
- Wash your hands after handling your dog if ringworm or mange is possible.
- Avoid tea tree oil, essential oils and human creams.
How vets diagnose the cause
Your vet will take a history and examine the skin, then may recommend:
- Flea combing
- Skin scrapings and hair plucks to look for mites
- Skin cytology to look for bacteria and yeast
- Ringworm testing
- Blood tests for hormonal disease
- A diet trial for food allergy
- Skin biopsy for unusual cases
How it is treated
Treatment targets the cause: parasite treatment for fleas and mites, medicated shampoos and medication for infection, antifungal treatment for ringworm, allergy management, or medication for hormonal disease. Most dogs' coats grow back within weeks to months once the cause is controlled.
FAQ
Can stress make my dog lose hair?
Stress can cause increased shedding and licking, but medical causes are more common and should be checked first.
Will my dog's hair grow back?
Usually, once the cause is treated. Scarred areas may stay thin.
Can I catch my dog's hair loss problem?
Ringworm and sarcoptic mange can spread to people. Most other causes cannot.
Why is my dog losing hair on the tail?
Fleas, allergies and hormonal disease are common causes. A vet can help work out which.
Talk with a vet
A Dial A Vet veterinarian can look at photos of your dog's coat and skin, discuss the likely causes, and advise on what tests your local vet may recommend. Book a Dial A Vet consult.
References
- Merck Veterinary Manual: Mange in dogs and cats
- Mueller RS, Rosenkrantz W, Bensignor E, et al. Diagnosis and treatment of demodicosis in dogs and cats: clinical consensus guidelines of the World Association for Veterinary Dermatology. Veterinary Dermatology. 2020;31(1):4-25.
- Moriello KA, Coyner K, Paterson S, Mignon B. Diagnosis and treatment of dermatophytosis in dogs and cats: clinical consensus guidelines of the World Association for Veterinary Dermatology. Veterinary Dermatology. 2017;28(3):266-e68.
- Merck Veterinary Manual: Flea allergy dermatitis
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.
