Dandruff in dogs: causes, a simple test and when to act

Reading time 5 min · Level 1: Why the symptom happens

The short answer: A little dandruff in the coat after a winter of dry indoor air is common and rarely dangerous. Still, a healthy dog does not normally have much dandruff, so when the flakes become plentiful or greasy or keep coming back there is usually a cause underneath. The most common are dry skin, seborrhoea following another skin disease, Cheyletiella mites and hormonal conditions such as an underactive thyroid. If the dandruff moves or the dog is itchy, it should see the vet.

What dandruff actually is

Skin renews itself all the time. New cells form at the bottom, travel upwards and come loose as an invisible dust. Dandruff appears when turnover runs too fast or when the cells come off in clumps rather than one by one. They then show up as white or yellowish flakes in the coat, in the dog's bed and on your dark trousers.

There are two main types and they point in different directions. Dry dandruff is small, white, light flakes in a dull coat. Greasy dandruff is larger, yellowish flakes that stick in a coat that feels tacky and often smells rancid. The greasy type is more often linked to a skin disease or an infection and is less often something you can sort out at home.

Six common causes

1. Dry skin. Heated indoor air in winter, frequent baths with the wrong shampoo or shampoo that is not rinsed out properly give dry, flaking skin. The dandruff is fine, spread evenly over the body and often comes and goes with the seasons. This is the cause you can most often influence yourself.

2. Seborrhoea. An umbrella term for skin that produces too much scale and becomes abnormally dry or abnormally greasy. According to AniCura, roughly one in five dogs with seborrhoea is born with it, while most have another skin disease behind it, such as allergy¹. Seborrhoea also makes the skin more prone to infection, which can bring odour and more flakes in a vicious circle.

3. Cheyletiella mites. This mite lives in the outermost layer of the skin and causes dandruff that often sits along the back towards the tail. The mites are about half a millimetre long and can look like dandruff that moves, hence the name walking dandruff². Puppies and young dogs are affected most³ and some dogs carry the mites without symptoms⁴. The mites spread between dogs, can pass to cats and rabbits and cause itchy bites in people. They survive for a few weeks off the dog².

4. Hormonal conditions. An underactive thyroid, hypothyroidism, develops slowly and often gives a dry, thin coat together with tiredness, weight gain and a dog that feels the cold⁵. Cushing's disease can also change skin and coat¹. Here the dandruff is only one of several signs and the vet is looking at the whole picture.

5. Allergy and infections. Allergic skin is irritated skin and irritated skin flakes. Yeast and bacteria often give greasy dandruff with an odour. There is more about itching and allergy in our article on dogs that scratch.

6. Diet. Skin and coat need protein and fat. An adult dog on a complete diet normally gets what it needs, so a poorer coat is rarely a sign of deficiency¹. Unplanned home-cooked food or a very low-fat weight loss diet are the exceptions worth looking at.

A simple test at home

Brush the dog over black paper or a dark towel for a few minutes, especially along the back. Then look closely, ideally with a magnifying glass or your phone camera zoomed in. Flakes that lie still are dandruff. Flakes that crawl are a reason to book an appointment. Black specks that turn reddish brown when you drip water on them are flea droppings, which is another thing that needs dealing with.

When to see the vet

The same week if the dandruff moves, if other pets in the household get dandruff or itch, or if you get itchy spots yourself. It may be Cheyletiella, in which case all animals need treating at the same time². Also if the dandruff comes with itching, sores, bald patches, odour or a greasy coat, or if it is a puppy.

Within a few weeks if the dandruff does not improve even though you have changed washing and humidity, or if the coat changes without explanation in an adult dog. If the dog has also become tired, gained weight or started drinking more, mention it. It is exactly that combination that makes the vet take a thyroid blood test⁵.

What you can do yourself

Brush more often. Brushing removes loose flakes and spreads the skin's own oils. A few minutes every day does more than one long session a week.

Wash the right way. Lukewarm water, a mild dog shampoo, then rinse until the water runs completely clear. Shampoo residue dries the skin. Human shampoo is made for different skin and is not suitable for dogs.

Raise the humidity. A bed some distance from the radiator and a humidifier in the room where the dog sleeps in winter.

Review the diet. A complete food in the right amount is enough for most dogs. If your dog has lost a lot of weight or eaten a one-sided diet for a long time, talk to your vet before adding anything.

Change one thing at a time. Give each change three to four weeks. Skin renews itself slowly and what you see in the coat today started several weeks ago.

Frequently asked questions

Is dandruff in dogs dangerous?

A little dry dandruff in a dog that is otherwise well is rarely dangerous. It is what comes with it, such as itching, odour, a greasy coat or tiredness, that decides whether it needs investigating.

Can I catch my dog's dandruff?

Ordinary dandruff is not contagious. Cheyletiella mites, however, can cause itchy bites in people². If you get red, itchy spots on your arms or stomach while your dog has dandruff, mention it to the vet.

How often should I bathe a dog with dandruff?

It depends on the cause. With dry skin, too many baths are part of the problem. With seborrhoea, the vet may instead recommend more frequent baths with a special shampoo for a period. Follow the plan you agree together.

Do puppies have more dandruff?

Puppies can get a little dandruff as the coat changes, but they are also the group most often affected by Cheyletiella³. Dandruff in a puppy is therefore worth showing the vet.

That was the short answer. If you have a question about your own pet, email us at info@herbiovet.se. We reply within one working day.