Brachycephalic dogs: health issues every owner should know

If you share your home with a Pug, French Bulldog, British Bulldog, Boston Terrier, Shih Tzu or Pekingese, you already know that flat face is a big part of the appeal. It's also the reason these breeds need a different level of care than a longer-nosed dog. The very features that make them so recognisable – a short muzzle, a broad rounded skull, big round eyes and a compact wrinkly face – come from selective breeding that has squeezed a normal amount of tissue into a much smaller space.

That doesn't mean every flat-faced dog is destined for a life of ill health, but it does mean owners need to know what to watch for. Breathing difficulty, eye injuries, skin infections, dental crowding and a much higher risk of overheating are all more common in brachycephalic ("short-headed") breeds than in dogs with an average-length muzzle. Many of these problems are manageable with the right daily habits, and some need veterinary treatment to fix properly.

This guide walks through the main health issues linked to flat faces, what causes them, the signs to look out for, and the practical steps that make the biggest difference day to day.

What makes a dog "brachycephalic"

Brachycephalic simply means short-headed. In these breeds, the bones of the skull and jaw are shortened, but the soft tissue inside – the tongue, soft palate, nasal lining and windpipe – hasn't shrunk to match. The result is a mouth and airway that are more crowded than in a dog with a typical head shape. The same mismatch affects the eye sockets, which are shallower, and the skin, which folds and wrinkles because there's more skin than face to cover.

Common brachycephalic dog breeds include the Pug, French Bulldog, British (English) Bulldog, Boston Terrier, Shih Tzu, Pekingese, Cavalier King Charles Spaniel and Japanese Chin, though the degree of flat-facedness – and therefore the health risk – varies a lot between individual dogs, even within the same breed.

Breathing problems (BOAS)

The best-known and most serious issue is Brachycephalic Obstructive Airway Syndrome, usually shortened to BOAS. According to PDSA, BOAS happens because flat-faced breeds have "a normal amount of tissue packed into a much shorter head," which leads to narrow nostrils, crowded nasal passages, an overlong soft palate and a narrower windpipe. Air simply has further to squeeze through less space.

Signs of BOAS include:

• Noisy breathing, snoring or snorting, even at rest
• Laboured or effortful breathing
• Struggling to exercise, play or keep up on walks
• Choking, gagging or vomiting after eating or drinking
• Disturbed sleep, or needing to sleep sitting up
• Collapsing or turning blue around the gums in severe cases

Many owners think the snuffling and snoring of a flat-faced dog is just part of the breed's charm – but PDSA is clear that these noises are a sign the dog is struggling to breathe, not a quirky personality trait.

Vets Now notes that the problem is progressive: it tends to worsen with age and with weight gain, because extra tissue around the throat narrows the airway further. Research reported by Vets Now also found that French Bulldogs with moderate to severe narrowing of the nostrils are around 20 times more likely to develop BOAS than those with normal nostrils, which shows just how much a single visible feature – tight, pinched nostrils – can predict a much bigger underlying problem.

Mild cases can sometimes be managed with weight control, a harness instead of a collar, and avoiding heat and overexertion. More affected dogs often benefit from surgery to widen the nostrils and shorten the soft palate, and outcomes tend to be better the earlier this is done, before the airway has had years to become inflamed and swollen from the extra effort of breathing.

Eye problems

Brachycephalic breeds have shallow eye sockets, which is part of why their eyes look so large and prominent. Unfortunately, this same feature leaves the eyes more exposed and less protected. The Kennel Club explains that a shallow socket can mean a dog isn't able to blink fully, leaving part of the cornea permanently exposed and prone to drying out, while prominent nasal folds can rub directly against the eye surface.

This combination makes flat-faced dogs far more prone to corneal ulcers – painful scratches or erosions on the surface of the eye. A peer-reviewed study of risk factors for corneal ulceration found that dogs with a brachycephalic skull shape were around 20 times more likely to develop ulcers than non-brachycephalic dogs, and that visible nasal folds roughly doubled to quintupled that risk further depending on how prominent they were. Breeds most affected in that study included the Pug, Pekingese and Shih Tzu.

Watch for:

• Squinting, or one eye staying part-closed
• Redness, cloudiness or a blue-ish tinge to the eye
• Excessive blinking, watering or discharge
• Rubbing at the face or pawing at the eye

Corneal ulcers can worsen quickly in these breeds, sometimes within hours, so the Kennel Club recommends treating any sudden eye discomfort as urgent rather than waiting to see if it settles. Treatment ranges from antibiotic drops and a protective collar for a simple ulcer, through to corneal surgery for deeper or non-healing ones. Some dogs with recurrent problems benefit from surgery to remove excess nasal folds so they stop rubbing on the eye.

Skin fold dermatitis

The same excess skin that gives flat-faced breeds their wrinkled charm also creates warm, moist folds where bacteria and yeast thrive. The Kennel Club describes how tears, saliva, food and general moisture collect in facial folds and around the tail base, creating ideal conditions for infection.

Signs of skin fold dermatitis include:

• An unpleasant, yeasty odour from the folds
• Redness, sore or puffy skin
• Brown or pus-like discharge
• Visible discomfort, scratching or rubbing the face on furniture

Daily cleaning of the folds – gently wiping away debris and moisture, then drying thoroughly, especially after meals, drinking or bathing – is the single most useful thing an owner can do to prevent flare-ups. If an infection does take hold, a vet will usually take a sample before prescribing topical or oral antibiotics or antifungals. Dogs with severe, recurrent fold infections sometimes have the folds surgically reduced to stop the cycle of chronic irritation.

Dental overcrowding

Flat-faced dogs still grow a full set of adult teeth, but they have to fit into a jaw that's considerably shorter than in other breeds. That mismatch forces teeth to erupt at odd angles, rotate, or overlap one another, trapping food, hair and plaque in the gaps. Research on brachycephalic breeds has found around a 25% increased risk of dental problems compared with dogs of normal skull length, largely because overcrowded teeth are so much harder to keep clean.

Left unmanaged, this crowding accelerates periodontal disease – inflamed gums, tartar build-up, bad breath and, eventually, loose or painful teeth. Regular brushing, dental chews designed for the purpose, and annual dental checks at the vet all help, and some dogs benefit from a professional scale and polish under anaesthetic more often than a longer-nosed dog would need. Our Pet Calorie Calculator can help you keep portion sizes in check too, since a lean dog puts less pressure on an already crowded mouth and airway.

Overheating and heatstroke risk

Dogs cool down mainly by panting, moving air over the moist surfaces of the tongue and airway. In a flat-faced dog, the airway that's meant to shift that cooling air is already narrower and more obstructed than normal, so the whole system is far less efficient.

A review of the evidence on brachycephalic dogs and heatstroke, published in the peer-reviewed literature, found that flat-faced dogs had significantly higher odds of heat-related illness than dogs with an average muzzle length across several studies – including higher odds of heatstroke during exercise, in hot environments, and in parked vehicles. Some individual breeds, such as Bulldogs, showed particularly high odds compared with Labradors in the same research. A separate hospital-based study cited in the same review found brachycephalic breeds made up 29% of heat-related illness cases despite being only 16% of the general patient population – a clear sign they're over-represented in emergency heat cases relative to their numbers.

Practical steps that make a real difference:

• Walk in the cool of early morning or late evening in warm weather, and skip exercise entirely on very hot or humid days
• Never leave a flat-faced dog in a car, conservatory or caravan, even briefly and even with a window open
• Keep to a healthy weight, since extra weight around the neck and chest narrows the airway further
• Provide constant access to fresh water and a cool, shaded, well-ventilated place to rest
• Learn the early signs of heat stress – heavy panting, bright red gums, drooling, wobbliness or collapse – and treat any of these as a vet emergency

Birth and breeding difficulties

Health risks in brachycephalic breeds aren't limited to the individual dog – they extend to breeding females too. Research from a large UK veterinary database, reported by Today's Veterinary Practice, found that French Bulldogs were around 15.9 times more likely to experience a difficult birth (dystocia) than crossbred dogs, with Boston Terriers, Pugs and Chihuahuas also showing sharply elevated risk. Among French Bulldogs that did experience a difficult birth, caesarean delivery was needed roughly 2.4 times more often than in crossbreeds, and the same research found that around a quarter of puppies born during difficult labours didn't survive.

The underlying reason is straightforward anatomy: a relatively large puppy head has to pass through a birth canal shaped by a body that's been bred for a compact, broad build. This is one of the clearest examples of how extreme conformation creates welfare problems that go well beyond appearance, and it's a key reason why responsible breeders health-test and why casual or backyard breeding of these breeds carries real risk to the mother.

Everyday care that helps every flat-faced dog

Regardless of which specific issues affect your dog, a few habits benefit almost every brachycephalic breed:

• Keep them lean. Excess weight makes breathing, overheating and joint strain all worse. A body condition check at every vet visit is worthwhile.
• Use a harness, not a collar. Any pressure on the neck adds to airway strain that's already a challenge.
• Build fitness gradually and manage exercise expectations. Short, gentle, regular walks usually suit these breeds better than long or vigorous sessions, and it's fine to adjust based on how your individual dog copes.
• Clean facial folds daily and dry them thoroughly.
• Brush teeth regularly and get dental checks at routine appointments.
• Know your dog's normal. Because snoring and snorting are so common in these breeds, it can be hard to spot when things are getting worse. Keeping a simple note of how your dog manages on walks, in heat, and at rest makes changes easier to notice.

Choosing a healthier flat-faced dog

If you're planning to get a Pug, French Bulldog or similar breed, both the Kennel Club and welfare charities including the RSPCA and Battersea encourage prospective owners to prioritise health over extreme looks. Battersea advises asking breeders directly about BOAS assessments, seeing both parents where possible, and choosing dogs with visibly longer muzzles, more open nostrils and less exaggerated features within the breed standard. Adopting from a rescue is another route worth considering, since charities such as Battersea regularly rehome flat-faced dogs and can advise on the ongoing care a particular dog is likely to need.

If you're still weighing up whether a flat-faced breed fits your lifestyle and budget, our free Pet Ownership Quiz is a useful starting point for thinking through the realities of day-to-day care before you commit.

When to see your vet

Contact your vet promptly if you notice any of the following in a brachycephalic dog:

• Breathing that sounds worse than usual, or breathing that looks effortful even at rest
• Collapse, fainting, or blue or purple gums
• Squinting, redness or cloudiness in an eye
• Sore, smelly or discharging skin folds that aren't improving with cleaning
• Heavy panting, drooling, wobbliness or lethargy in warm weather
• Reluctance to eat, or repeated vomiting or regurgitation after meals

Many of these signs can develop or worsen quickly in flat-faced breeds, so it's always better to get things checked early rather than wait and see.

*This is general guidance, not a substitute for advice from your vet, who can assess your individual pet.*

Sources

• PDSA — BOAS: breathing problems in flat-faced dogs (pdsa.org.uk).
• Vets Now — what you need to know about flat-faced brachycephalic dogs (vets-now.com).
• The Kennel Club — eye problems in brachycephalic dogs (royalkennelclub.com).
• The Kennel Club — skin problems in brachycephalic dogs (royalkennelclub.com).
• RSPCA — advice on brachycephalic (extreme conformation) pets (rspca.org.uk).
• Battersea Dogs & Cats Home — flat-faced dogs and cats: what you need to know (battersea.org.uk).
• Peer-reviewed study on conformational risk factors for corneal ulceration in dogs, PLOS ONE, via PubMed Central (pmc.ncbi.nlm.nih.gov).
• Peer-reviewed review of heatstroke risk in brachycephalic dogs, via PubMed Central (pmc.ncbi.nlm.nih.gov).
• Today's Veterinary Practice — reporting on RVC VetCompass research on French Bulldog birthing difficulties (todaysveterinarypractice.com).