Why Does My Dog Smell Sour?

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Why Does My Dog Smell Sour?

Most dogs have an odor of some sort, but sometimes it’s not all that sweet-smelling!

If your dog has smelt ‘off’ recently then there could be several reasons for this.

We are going to explore why your dog might have developed a sour smell and what you can do to help improve things.

Some sour smells may include smelling like sour milk.

Let’s get into why your dog may suddenly have this bad smell.

7 Reasons Why Your Dog Smells Like Sour Milk

Why Does My Dog Smell Sour

There are many reasons why your dog might smell sour, maybe even like milk that’s gone bad!

Let’s explore each in turn:

Your Dog Has Rolled In Something Gross

The smell could be due to something straightforward like your dog rolling in something unpleasant.

Dogs love to roll, it’s in their nature, and the smellier the better usually.

If your dog has rolled in the garbage, fox poop, or on a dead fish at the beach then it will change his scent.

Sometimes these smells could smell like sour milk, especially if your dog has rolled around in garbage.

We are not entirely sure why dogs do this, but it is thought to be an instinct to help mask their own smell, allowing them to sneak up on prey.

Wolves have been seen rolling in the dung of plant-eating animals and on carcasses before hunting.

While you won’t be able to stop a dog from exhibiting its normal behaviors, you can at least fix the smell by giving him a bath afterward.

Your Dog Has A Dirty Collar Or Bedding

It’s worth looking at your dog’s possessions.

Perhaps his collar or harness needs a good wash?

Bedding too can become a bit pungent if it hasn’t been cleaned recently.

Ingrained dirt and skin oils can leave your dog’s belongings smelling a bit off, so take care to wash these at regular intervals to help your pet stay at his best, especially if he likes rolling in pungent things.

Some dog collars (leather, flea repellent) can also have an odor that smells like something sour.

If you have recently given your dog a new collar, check to see if that sour smell is actually coming from the new collar.

Your Dog Has A Skin Or Ear Infection

If your dog has a skin or an ear infection, then this could affect his natural smell.

Yeast and bacterial infections can give your dog a sour odor, alongside sore and irritated skin.

These infections usually occur due to an underlying problem such as a skin allergy, parasites, or perhaps even a foreign body lodged somewhere (grass seed or thorn).

Alternatively, it could be because your dog has excessive skin folds and wrinkles, creating warm, damp areas prone to infection.

As well as a change in smell, symptoms of ear and skin infections include:

  • Excessive scratching or licking
  • Red/pink, inflamed skin
  • Crusts or spots
  • Hair loss
  • A greasy coat

Skin and ear problems can affect any breed, but usually for different underlying reasons.

If your West Highland White Terrier, Bulldog, or Labrador smells sour, then get them checked out.

Your vet will help treat the infection with prescription medications or shampoos, but will also discuss the underlying cause to try and stop the problem from happening again in the future.

Your Dog Has Anal Gland Issues

The anal glands are two small sacs just inside your dog’s bottom.

These contain scent-marking material which usually express themselves when a stool passes through, pressing on them.

In some dogs, this doesn’t happen though, and the glands become full, causing discomfort.

These impacted anal glands may leak a little causing your dog to smell unpleasant.

This material could leak on his bedding or your sofa too, with some people saying it smells like vinegar but others comparing it to rotten fish or a metallic smell.

Often dogs with this problem will be irritated making them lick excessively and scoot their bottom on the floor.

These glands need emptying by your vet to relieve your dog’s symptoms.

They could become infected and even rupture if ignored, causing your dog considerable pain.

Some dogs are prone to anal gland issues and need regular expression, whereas others never suffer.

There are some measures you can take to reduce the risk of anal gland impaction:

  • Increasing the fiber in the diet through supplements to create bigger firmer stools which will help your dog empty his glands himself.
  • Being overweight can predispose to anal gland problems, so keep your dog at a healthy body weight.
  • Manage any skin allergies, as some dogs with allergies can present with recurrent anal gland issues. 
  • Get your dog’s anal glands checked at the first indication that there is a problem.

Your Dog Has A Urinary Tract Infection

A sour smell down below may be because of a urinary tract infection, or because of an infection in the vagina or penis.

Sometimes urinary incontinence, causing stale urine on your dog’s skin, fur, or bedding, could create a sour smell too.

You may also notice other symptoms if your dog has issues with his urinary tract, such as discomfort when urinating, a change in the color of the urine, urinary accidents, or going little and often.

If you think your dog has a possible infection, then you should seek help from your veterinarian.

They will be able to help confirm a diagnosis and provide appropriate treatment for your pet, which will in turn help improve his sour odor.

Your Dog Has A Dental Disease

Your dog may smell like sour milk if he has bad teeth and gum disease.

High levels of bacteria associated with trapped food, excessive amounts of calcified tartar, and inflamed gums can create quite an unpleasant smell.

To avoid this, you should check your pet’s teeth regularly.

You should also train your pet gradually to accept daily teeth brushing, to try and stop the dental disease from occurring in the first place.

If you suspect your dog has a problem with his teeth or gums, then get him checked over by your veterinarian.

They may advise surgery to remove any problematic teeth, as well as scale and polish to clean up the rest.

Your Dog Has Kidney Disease

If your old dog smells sour, then as well as some of the other conditions listed above, they could actually be suffering from kidney disease.

Animals that have kidney failure may start to have sour-smelling breath due to a build-up of toxins in their system.

Other signs of kidney disease include:

  • Increased thirst
  • Reduced appetite
  • Weight loss
  • Lethargy
  • Gastrointestinal upsets

Your vet will need to take blood samples to confirm a diagnosis.

Sadly, there is no cure for chronic kidney failure in older patients, but steps can be taken to improve things and slow the progression of the disease.

How To Get Rid Of The Sour Smell On My Dog?

It depends on the cause of your dog’s sour smell as to how best to tackle it.

If you think your dog has one of the listed health complaints above, then it may require veterinary treatment to improve his odor.

However, if you believe the smell is because he’s rolled in something or his belongings are well overdue a wash, then you can easily take steps to remedy this.

Use a dog-specific shampoo to bathe him in, just make sure you don’t wash him too regularly, only when he needs it.

Otherwise you could end up stripping his coat of its natural oils, which can lead to other skin irritations.

When Should I Take My Dog To A Vet For His Sour Smell?

You should always take your dog to the vet if you have any concerns about their health.

Things like skin and ear infections will do best with a formal diagnosis and prescription medications, rather than attempts to self-treat with products bought online.

Similarly, bad breath is usually an indicator that something has gone awry, either with the mouth and teeth or because of an underlying health issue.

This will require appropriate medical attention.

Most conditions do best when treated promptly, so don’t delay and get your dog checked if you are worried.

My Dog Smells Like Sour Milk

Conclusion On Why Your Dog Smells Sour

If your dog smells a little ‘off’ then it’s either because he needs a good bath, or because he has an underlying health condition.

If you are struggling to identify the cause of his sour smell, then get him checked over by your veterinarian.

They will help you to work out what’s going on and be able to suggest an effective course of action to get your dog smelling sweeter again.


What Causes A Dog’s Skin To Smell Sour?

Skin infections can make your dog’s skin smell unpleasant.

Look out for other symptoms such as increased itchiness, hair loss, and inflammation.

However, your dog’s skin may simply smell sour because he’s rolled in something disgusting!

Why Does My Dog Smell Sour Even After A Bath?

If a bath with a good quality dog shampoo hasn’t improved your dog’s odor then there is likely to be something more fundamental going on.

Various underlying health conditions can cause your dog to smell sour, so take a look at his teeth, ears, and skin.

If you still aren’t sure, then take him to your vet for a check-up as the sour smell could be caused by an underlining health issue.

Dr Rebecca MacMillan

Rebecca MacMillan

Rebecca is a companion animal vet who lives and works in the UK. She graduated from The Royal Veterinary College (London) in 2009 and since then has gained a wealth of experience in all aspects of veterinary care. She has also recently completed a British Small Animal Veterinary Association postgraduate qualification in medicine, passing with commendation. Outside of work, she enjoys writing on a variety of pet health and behaviour topics, as well as spending time with her young family and her flat coated retriever, George.

Rebecca is currently a Veterinary Surgeon at Vets4Pets – Find her on LinkedIn

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