What this means
The look of the coat partly reflects how a dog is doing overall. The skin grows the hair, and it needs the nutrients the body takes in from food and properly working hormones and metabolism. That is why a dull coat without a sheen is sometimes the first sign that something is wrong beyond the skin itself.
Notice exactly what has changed about the coat. A dry, coarse or woolly coat is different from hairs that break, fall out easily or become sparse. Also note whether the coat has gone dull all over or only in places, and whether flaking, greasiness, bald spots or darkening of the skin have appeared with it.
It matters whether other things are changing alongside it: weight, appetite, the look of the stools, thirst, urination and energy. A dog that eats a great deal but stays thin, or one that drinks and urinates much more, may have an internal cause and not just a coat problem. In some dogs a dull or woolly coat is part of an inherited coat or skin trait, which is also worth discussing with your vet.
Brushing and bathing do not by themselves solve the cause. Write down when the coat changed and show it to your vet so they can decide which tests are needed.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
-
Digestion and absorption problems
When the body does not take up enough nutrients from food, the coat becomes dull and poor. Weight loss, bulky or greasy stools and a big appetite may go along with it.
-
Thyroid or other hormone problems
Hormonal imbalances change the texture of the coat: it becomes dry, thins or breaks. Energy and weight often change too.
-
Inflammation of the skin's oil glands
When the oil glands of the skin are inflamed, hairs turn dull and break, and flaking appears. Changes may begin on the head, back or ears.
About the condition: Sebaceous adenitis -
Kidney tubule and metabolic disorders
Some metabolic diseases first give themselves away through a coat without sheen, together with increased thirst and urination.
About the condition: Fanconi syndrome -
Inherited coat changes
In some dogs a dry or woolly coat is part of an inherited coat or hair-growth trait. A vet should assess whether it is linked to illness.
-
Parasites and skin disease
External parasites, fungus or infection damage the skin and hair, so the coat looks dull, sparse and uneven.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Whether the coat is dull all over or only in places
- Whether hairs are breaking, falling out easily or have become woolly
- Whether there is flaking, greasiness, bald spots or darkened skin
- Whether weight and appetite have changed
- What the stools are like: amount, colour, consistency
- Whether thirst, urination and energy have changed
When to book a routine visit
Book a visit if the coat has become dull, dry or brittle and this has lasted more than a few weeks, particularly if weight, appetite, stools, thirst or energy are changing too.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Alopecia X (black skin disease) Skin and coat Alopecia X is a condition in which the hair growth cycle is disrupted: the coat gradually thins until bald patches appear on the body and the exposed skin darkens. It neither hurts nor itches, so it affects the dog's looks more than its wellbeing. Hormonal disorders can look very similar, though, so changes in a balding dog's coat are worth showing to a vet.
- Exocrine pancreatic insufficiency (EPI) Digestion and liver This is a condition in which the pancreas doesn't produce enough digestive enzymes, so food passes through almost undigested and the body misses out on the nutrients it needs. As a result, a dog can eat for two and still lose weight. A vet confirms whether it really is EPI with tests.
- Fanconi syndrome Kidneys and bladder Fanconi syndrome is a disorder of the kidney tubules in which the kidneys can no longer return to the blood substances the body should keep, such as glucose, salts and amino acids. These substances are lost in the urine, so the body starts to run short of them. Over time the condition can damage the kidneys.
- Sebaceous adenitis Skin and coat Sebaceous adenitis is a skin disease in which inflammation damages and over time destroys the sebaceous glands, which make the oils that protect the skin and coat. Without this protective layer the skin dries out and flakes, the hair breaks and falls out, and the skin becomes more prone to infection. The disease is thought to be inherited and is long-lasting, and what lies behind particular skin changes is for a vet to work out.
- Intestinal worms Parasites Intestinal worms are parasites that live in a dog's gut: roundworms, tapeworms, hookworms and whipworms. Any dog can become infected, and puppies even before birth or through their mother's milk. Some dog worms are dangerous to people too, especially children; which worms a dog has is for a vet to establish from a stool sample.
Body systems: Skin and coat Digestion and liver Kidneys and bladder Parasites