Dogs and dry indoor winter air: skin, coat, nose and pads, age by age

Quick answer

Brushing does more in winter than remove hair. It lifts the coat off the skin and spreads the oil the skin is producing more slowly.

Winter dryness in dogs is an indoor problem, not an outdoor one. Cold outside air carries very little water, and heating it to living-room temperature drops the relative humidity in the room a long way.

The result is faster water loss straight through the skin, a coat that crackles with static, a nose and paw pads that crust, and a dog that scratches more from about the time the heating comes on until about the time it goes off.

• The signs follow the heating, not the temperature. Owners in mild climates with poor insulation and a hot radiator see it as clearly as owners in Helsinki.
• Flaking with normal skin colour is usually barrier loss. Flaking with redness, smell, or thickened skin is a disease and needs a diagnosis.
• Winter itch is often house dust mite allergy rather than dryness, because sealed heated homes concentrate exactly that allergen.
• A dry, cracked nose that never improves in spring is a different problem from a nose that crusts every January.
• Puppies and seniors dry out faster than adults, for different reasons, and the senior is the one at risk of a burn.

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Never let a dog that cannot easily move away sleep pressed against a radiator, a wood stove, a heat lamp or a heat pad.

Arthritic, elderly, heavily sedated and post-anaesthetic dogs seek heat and then stay put because getting up hurts. Contact burns develop slowly at temperatures that feel merely warm to a hand, and because the coat hides the skin, the injury is usually found days later as a firm, dark, painful patch that later sloughs. These wounds are deep, slow to heal, and frequently need surgery.
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Decide in 60 seconds

Why heated air dries a dog out

Air holds water in proportion to how warm it is. Cold winter air is already close to saturated at a low absolute water content, so when you draw it into a house and warm it up, the amount of water in it does not change but the amount it could hold rises sharply. The relative humidity falls.

That dry indoor air pulls moisture continuously out of any wet surface, including skin.

The outer layer of a dog's skin works like a brick wall. Flattened dead cells are the bricks and a lipid mixture is the mortar. When the mortar is intact, water loss through the wall is slow. When the air is dry, water leaves faster, the outer cells shrink and separate, and they come away as visible flakes.

Two things then follow. The barrier is now leakier in both directions, so allergens and bacteria get in more easily. And the nerve endings under a thinned barrier are more easily triggered, so the dog feels itch at a level of stimulation that would not have registered in September.

This is why winter itch in a dog with no allergy at all is real, and also why winter is when an allergic dog gets much worse rather than slightly worse.

The coat matters too. A double-coated dog carries a dense insulating undercoat that traps a layer of humid air against the skin. That microclimate is a large part of why northern breeds tolerate dry cold well. Strip that undercoat with aggressive de-shedding, or clip it off, and you have removed the dog's own humidity buffer.

Sebum is the other half. Sebaceous glands feed oil up the hair shaft, and brushing is what distributes it. In a dog that is brushed rarely, the oil sits at the base and the ends of the coat go dry and brittle regardless of the room.

What a healthy winter coat and skin look like

Part the coat over the back, the flank and the belly in good light, ideally daylight at a window.

Skin should be a pale, even colour with no redness, no rash, and no dark patches that were not there in summer. A few flakes on a brush is normal. A shower of scale that lands on a dark floor when you stroke the dog is not.

The coat should lie flat and spring back. Static is expected in a dry room, but a coat that stands away from the body permanently and feels coarse has lost its oil.

The nose should be cool, and it can be dry or moist without meaning anything at all. What matters is the texture. A normal nose has a fine cobbled surface. Winter hyperkeratosis adds a raised, dry, sometimes frond-like build-up on top of that texture, most often at the top edge of the nose.

Paw pads should be firm, with a slightly rough surface and no deep splits. Look between the toes and at the web, which stays damper and is where cracks and infection start.

Ear leather is a good early warning site. Run a thumb along the outer edge of the ear flap: fine scale there often shows before anything is visible on the body.

The whole winter kit: a brush that reaches the skin, a comb to check for scale and parasites, a leave-on conditioner or emollient, and a towel for wet paws that would otherwise dry out further.

Age by age

Puppies.

A puppy has a soft coat with little undercoat and a large surface area for its body weight, so it dries out and chills faster than an adult in the same room. Puppy coat is also actively being replaced, which means loose hair, flakes and a period of looking scruffy that is normal.

The trap at this age is over-bathing. New owners bath a puppy every week because it smells of puppy, and each wash removes sebum the skin then has to remake in dry air.

The second trap is confusing a normal juvenile skin infection for dryness. Puppy pyoderma produces small pimples and crusts on the thinly haired belly and groin, and it needs treatment, not moisturiser.

Adults.

This is where the seasonal pattern becomes readable. An adult dog with a stable diet, stable parasite prevention and no disease should show mild scale and static and nothing else.

An adult who itches on a strictly winter schedule is the classic house dust mite picture: worse indoors, worse in bed, worst in the sealed months, better on holiday in a different house. That is a diagnosis worth pursuing, because it is manageable and it will not improve on its own.

Seniors.

Older skin is thinner, produces less oil, and heals more slowly. Coat regrowth after a clip can take much longer than an owner expects.

Seniors also lie down for longer in one position, so pressure points over the elbows and hocks build calluses, and those calluses crack in dry air and can become infected.

And seniors seek heat, which is where the burn risk in the danger box above comes from.

Any older dog whose coat quality drops noticeably over one winter deserves a proper look for an underlying cause rather than a bottle of oil. Hypothyroidism, Cushing's disease, kidney disease and cancer all announce themselves partly through the coat.

What is not just dry air

This is the part that decides whether you are managing a season or missing a disease.

Itch that stops the dog sleeping.

Barrier dryness produces mild, intermittent scratching. A dog that wakes to chew its feet, that has raw skin, or that cannot settle has something else, most commonly allergic skin disease with a secondary bacterial or yeast infection.

Anything with a smell.

Skin that smells musty or sour has yeast on it. Yeast loves the warm, occluded skin of the armpits, groin, ear canals and between the toes. It is treatable and it does not resolve with humidity.

Redness, spots, or dark thickened skin.

Pustules, circular crusts, or skin that has gone dark and leathery in the armpits and groin means an infection or a chronic inflammatory process, not water loss.

Flakes with mites in them.

Cheyletiella mites cause large scale that appears to move, which is where the name walking dandruff comes from. Sarcoptic mange causes ferocious itch with crusting on the ear margins, elbows and hocks, and it passes to people. Both are commonly written off as winter dryness for weeks.

Fleas in January.

Central heating keeps a house at flea breeding temperature all winter. Owners who stop prevention in autumn frequently get their worst infestation in midwinter, and flea allergy is intensely itchy from very few fleas. Check the rump and tail base, and comb over damp white paper to look for flea dirt that dissolves to a rusty smear.

A nose that changes architecture.

Simple winter hyperkeratosis adds material on top of a normal nose. Disease removes structure. If the cobbling flattens out, the nose loses pigment, or the junction between nose and haired muzzle becomes eroded or ulcerated, think immune-mediated disease such as discoid lupus, and get it looked at rather than creamed. In parts of southern Europe, the Mediterranean basin, Latin America and the Middle East, leishmaniasis also causes crusting around the nose and eyes and needs to be on the list.

Crusting around the eyes, muzzle and pads in a northern breed.

Siberian Huskies, Alaskan Malamutes and related breeds are prone to a zinc-responsive skin disease that looks like severe winter crusting and responds to supplementation prescribed and monitored by a vet. Guessing at zinc doses at home is not safe.

Dry coat plus other systemic signs.

Weight gain, lethargy, heat seeking, hair that does not grow back where it was clipped, and recurrent skin infections together point at low thyroid function. Increased drinking, a pot-bellied outline and thin skin point elsewhere. Either way it is a blood test, not a moisturiser.

A dog whose fat intake was recently cut.

Dogs on strictly low-fat diets, whether for pancreatitis, lymphangiectasia or weight loss, can become deficient in essential fatty acids, and skin is where that shows first. Correction takes weeks to months rather than days, because you are waiting for new skin cells and new hair to be built.

The inside of the ear flap and the outer edge of the leather show scale, redness and thickening before the body coat does. This is what healthy looks like: pale, clean, no crust along the margin.

The routine that keeps the barrier intact

The aim is to slow water loss and to stop yourself making it worse. Most of the work is subtraction.

Brush more, bath less.

Brushing distributes sebum and lifts the coat so air can move under it. Bathing removes sebum. In heating season, stretch the interval between baths and use a soap-free, moisturising shampoo when you do wash.

Rinse and dry properly.

Shampoo residue is itchy and drying. Rinse until the coat squeaks, then dry with towels and warm, moving air rather than hot air held in one place. A high-heat dryer close to the skin is a common cause of a burn on a dog that cannot tell you it hurts.

Deal with wet paws.

A paw that goes from snow or rain to a hot dry room dries out and cracks. Rinse off grit and de-icer, dry between the toes, and use a pad balm on pads that are already rough.

Raise humidity moderately.

A humidifier or simply drying laundry in the room where the dog sleeps helps. Aim for comfortable, not tropical.

Feed the barrier from the inside.

A complete diet already contains essential fatty acids. If a vet recommends an omega-3 supplement, that is a reasonable measure, and it will take weeks to show. Give it time before deciding it failed.

Keep parasite prevention running through winter.

What never to do

Do not put human moisturiser, petroleum jelly or cooking oil on a dog that licks. Whatever goes on the coat goes into the stomach, and a mouthful of oil causes diarrhoea in a small dog.

Do not use coconut oil as a fix for a nose or pad that is cracked and open. Grease over a fissure traps bacteria in it.

Do not clip a double coat to "let the skin breathe". The undercoat is the humidity buffer, and in many dogs it grows back unevenly or not at all.

Do not bath more often because the dog is flaky. That is the single most common way owners make winter skin worse.

Do not treat repeated ear infections as a winter nuisance. Recurrent ear disease in a dog is an allergy sign until proved otherwise.

Do not give zinc, vitamin A or high-dose supplements on your own initiative. Both zinc and vitamin A are harmful in excess, and the conditions they treat need to be diagnosed first.

Do not leave a dog outdoors longer to "toughen the coat". Cold does not build barrier lipids.

When to get help

Book an appointment this week for any of these:

• Itch that interrupts sleep, or skin the dog has made raw
• Any smell coming from the skin, ears or feet
• Redness, pustules, circular crusts, or skin that has darkened and thickened
• A pad crack that bleeds, or licking focused on one foot
• A nose that is losing texture or pigment rather than gaining crust
• Scale that persists into spring, or that appeared without a change in season
• Coat change alongside weight change, drinking change or lethargy
• Anyone in the household itching as well, which raises mites or fleas sharply

Go the same day for a suspected contact burn, a deep bleeding fissure, or a swollen, hot, painful foot.

The winter target: settled, not scratching, pads intact, and lying on a bed rather than against a radiator.

Bring these to the appointment, because they shorten the process considerably:

• When the signs started, relative to the heating going on
• Whether last spring cleared it completely
• Bathing frequency and the exact product used
• Diet, including any recent switch and any fat restriction
• Dates of the last flea, tick and worming treatments, and the product names
• Photographs of the nose, pads and worst-affected skin in daylight
• Whether other pets or people in the home are itching

A vet working this up will usually start with a physical examination and simple in-house tests: tape strips and skin scrapes for mites, yeast and bacteria, and a coat brushing for flea dirt. Those are quick and inexpensive and they rule out the treatable, contagious causes before anyone talks about allergy. If the picture points at a hormonal disease, blood testing follows. Allergy is diagnosed by ruling other things out first, which is exactly why the parasite and infection steps are not a waste of time.