Five summer health risks that catch dog owners off guard

Summer is the finest time of the year to have a dog. It is also, quietly, when some of the most serious and most preventable health emergencies happen, often to careful owners who simply did not see them coming. Five hazards account for the bulk of them, and none requires anything more than awareness and a little planning to avoid.

Heatstroke, and the trigger nobody expects

Heatstroke kills dogs, and it does so more often than most owners realise. A peer-reviewed study of UK emergency veterinary records from the 2022 heatwave found that one in four dogs treated for heatstroke died (Beard et al., 2024, Veterinary Record). The detail that ought to change behaviour, though, is the cause. The classic image is a dog shut in a hot car, and that danger is real: on a 22 degree day a parked car can climb past 47 degrees inside within an hour, and cracking the windows makes very little difference. But the car is not the main culprit. In that same study, over half of all heatstroke cases were brought on not by confinement but by exercise, by owners walking or running their dogs in conditions that were simply too warm for it.

The thresholds are easy to hold in your head. Once the temperature climbs above 20 degrees, shorten the walk. Above 25 degrees, walk only before nine in the morning or after six in the evening, when the day has cooled. And in a genuine heatwave, drop the midday outing altogether rather than risk it. Knowing the warning signs matters just as much, because heatstroke moves fast. Watch for heavy, laboured panting, excessive drooling, gums that have turned red or gone pale, staggering or collapse, vomiting, and confusion. If you see them, act at once: move your dog to a cool, shaded place, apply cool water, not cold and never iced, to the body and especially the neck, armpits and groin, and fan them to help it evaporate. Then telephone your vet before you set off, so the practice is ready and waiting when you arrive.

One group of dogs runs closer to the edge than the rest. French Bulldogs, Bulldogs, Pugs, Shih Tzus, Boxers and the other flat-faced, brachycephalic breeds are at markedly higher risk of heatstroke, because their shortened airways simply cannot move air, and therefore shed heat, as efficiently as a longer muzzle can. For these dogs many veterinary guidelines suggest easing off exercise once the temperature passes 18 degrees, a good couple of degrees lower than for other breeds, and it is a mistake to be reassured by a Frenchie who appears to be coping. By the time a brachycephalic dog looks to be struggling, it is often already in trouble.

Water that can kill within hours

The second hazard hides in exactly the still, warm water that looks so inviting on a hot day. Blue-green algae is not a plant but cyanobacteria, and some species produce toxins potent enough to kill a dog within hours of exposure. It shows itself as a greenish-blue scum or paint-like streaks across the surface of slow-moving or stagnant water, and it blooms most readily in the warm, still conditions that run from June through to September. Treat any suspect water as dangerous: if your dog has been in it, rinse them immediately with clean fresh water, stop them licking their coat, and go straight to a vet without waiting to see whether symptoms appear. The Environment Agency publishes UK bloom alerts at environment.data.gov.uk, which are worth checking before you let a dog swim in unfamiliar fresh water. And while you are near the coast, remember that seawater is its own, milder problem: a dog who drinks it will usually vomit, and the salt hastens dehydration, so keep fresh water on hand and offer it often enough that the sea never becomes the tempting option.

The seed that only travels one way

The third risk is the one owners most often underestimate, because it looks so trivial. Grass seeds peak between June and August, and the barbed, arrow-shaped seeds are built to catch in fur, pierce the skin and work their way inward, and the cruel part is that they cannot travel backward, only deeper. A seed that enters a paw can migrate through tissue and cause real damage if it is missed. The habit that prevents almost all of this costs a minute: after every walk through long grass, run a check between every toe on all four paws, around and inside the ear flaps, around both eyes, and around the nose and lips. If a seed has already found its way in, the dog will usually tell you, through obsessive licking of one particular paw, repeated head shaking, persistent sneezing, or an eye that weeps or holds itself closed. Any of those warrants a same-day trip to the vet rather than a wait-and-see, because a seed only ever gets harder to reach (PDSA).

Hot ground, and the burns you cannot see coming

The fourth hazard is underfoot. On a day when the air is a pleasant 25 degrees, dark tarmac in direct sun can climb past 50, hot enough to blister a paw pad, and dogs give very little warning before the damage is done. The test is simple and worth making a reflex: press the back of your hand flat against the surface and hold it there for seven seconds. If you cannot manage it in comfort, the ground is too hot for your dog to walk on, and you should wait for the cool of the evening or stick to grass.

The fifth risk is the one most owners never think about at all, which is that dogs get sunburned. Light-coated, short-haired and pale-skinned dogs are the most vulnerable, Boxers, Dalmatians, Whippets, Bull Terriers and Staffordshire Bull Terriers among them, and the places that burn are the thinly furred ones: the tips of the ears, the bridge of the nose, the eyelids and the belly. It is not merely a matter of a day's discomfort, because repeated sunburn raises the long-term risk of squamous cell carcinoma, a skin cancer (PDSA). The protection is straightforward with one firm rule attached: never use human sunscreen on a dog, because many human formulas contain zinc oxide, which is toxic to dogs and damages their red blood cells. Reach instead for a pet-specific product of SPF 15 or higher, work it into the ear tips, the bridge of the nose and any other exposed skin, and reapply it every couple of hours in strong sun. If your dog has pink or exposed skin and spends the summer outdoors, this is not a fussy extra. It is genuine, and widely overlooked, protection.

None of these five hazards should keep a dog indoors all summer. Between them they account for a great many of the season's avoidable emergencies, and every one of them yields to the same unremarkable things: an eye on the thermometer, a check of the water and the ground, a minute spent going over paws and ears, and the good sense to walk in the cool of the day. Get those into the rhythm of the season, and summer goes back to being simply what it should be, the best time of the year to have a dog.