Dehydration
Dehydration occurs when a dog or cat loses more fluid than it takes in, impairing organ function and requiring prompt attention.
Also known as Fluid Loss, Skin Turgor Test, Skin Tent Test
Water makes up a huge share of your pet's body weight, and even a small deficit throws things off balance. Dehydration happens when your dog or cat loses more fluid than they take in, whether from not drinking enough, vomiting, diarrhoea, heatstroke, fever, kidney disease, or diabetes. Because fluid carries oxygen and nutrients around the body and helps organs function properly, once losses outpace intake, blood flow and fluid volume drop, which reduces the delivery of oxygen to organs and tissues. Left unaddressed, this can progress toward kidney strain, collapse, and in severe cases death.
Mild dehydration is easy to miss because pets don't complain about it directly. Watch for a combination of these signs rather than relying on just one:
- Gums that feel dry, sticky, or tacky instead of moist and slick
- Thick, ropey saliva
- Reduced energy or unusual quietness
- Loss of appetite
- Sunken-looking eyes
- Skin that's slow to spring back when gently pinched between the shoulder blades
That last one, the skin tent or turgor test, is the check most people have heard of. You lift a fold of skin and see how quickly it falls flat again. It's a useful home screening tool, but vets caution it isn't foolproof. Dehydration below 5% is essentially undetectable on physical examination, and by the time skin turgor loss becomes obvious at around 6 to 8%, a pet has already lost a meaningful volume of body water. Age and body condition can also throw the test off, since overweight pets may show a falsely normal result despite being dehydrated, while very thin or elderly pets can appear tented even when they're actually fine. In clinic, vets combine that pinch test with checking gum moisture, capillary refill time (how fast colour returns after pressing on the gums), eye position, and sometimes blood tests to get a clearer picture.
Cats deserve a special mention here. Many naturally have a low drive to drink, so they often don't take in enough water on their own, which means dehydration can creep up quietly, especially in cats with kidney disease or those eating mostly dry food. Feeding wet food, offering multiple wide, flat water bowls, and keeping water fresh all help nudge intake upward.
If you spot several of the signs above, especially alongside vomiting, diarrhoea, lethargy, or heat exposure, it's worth calling your vet rather than waiting to see if things improve. Mild cases can sometimes be managed with small, frequent sips of water at home, but dogs with extreme dehydration typically need intravenous fluids to rehydrate safely, and a vet is best placed to work out both how dehydrated your pet is and what's actually causing it. Think of dehydration less as a standalone problem and more as a signal that something else, heat, illness, or an underlying condition, needs attention.
