Ichthyosis is a group of inherited conditions in which the outer layer of the skin does not form normally, so the skin builds up scale [1][3]. Most scaly skin in dogs has another cause: a review notes that most scaling disorders follow allergies, mites or other skin parasites, or hormone and metabolic disease [3]. So your vet looks for those causes first.
For flaky skin in general, see our post on dry, flaky skin in dogs.
What it is
A university dermatology handbook describes ichthyosis as a rare inherited problem with how the skin makes its tough outer layer. The main sign is scaling that ranges from mild to severe, and now and then the paw pads thicken [1]. Scale can be stuck to the skin, loose, or both [2].
A review explains that this outer layer keeps the body hydrated and shields it from the outside world. When it is built wrongly, the dog can lose water and is more open to skin infections and to allergy [4]. The same review says these conditions run from fairly harmless to fatal [4].
Which dogs are affected
The handbook lists reports in the Norfolk Terrier, Jack Russell Terrier, Golden Retriever, Labrador Retriever, American Bully, American Bulldog, Great Dane, German Shepherd Dog, Cavalier King Charles Spaniel and Chihuahua [1]. Each breed has its own gene change, but the dogs look alike: the shared sign is too much scale [1].
In Golden Retrievers, most cases are linked to a change in a gene called PNPLA1, and a second, rarer form is linked to a different gene [1][12].
How it is inherited
In almost all reported forms, a puppy has to get the faulty gene from both parents to be affected (autosomal recessive inheritance) [1]. The one exception so far is a single German Shepherd Dog [1]. Studies of Golden Retriever family trees point the same way [5][6], with one noting that a partly dominant pattern could not be excluded [6]. Family trees of Cavalier King Charles Spaniels with a related eye and skin syndrome also fit recessive inheritance [8].
DNA tests exist for some forms, such as the two Golden Retriever types and the American Bulldog and American Bully form, and they can show which breeding dogs carry the gene [1][12]. The handbook advises against breeding affected dogs [1][2]. Your vet can tell you whether testing is useful for your dog.
What you may notice
- Scale: large white, grey or tan flakes, stuck down or loose, often most obvious along the body [1].
- Paw pads: some dogs have thick, hard paw pads [1][2]. See our post on paw problems in dogs.
- Golden Retrievers: usually a milder form. One study saw small to large white flakes that turned darker over time, and belly skin that was darker and felt rough like sandpaper [5]. The handbook adds that signs can flare and settle [1].
- Other breeds: American Bulldogs and American Bullies tend to be worse, with red skin and brownish scale on the less hairy areas [1][10]. Jack Russell Terriers can have thick, heavy scale over the whole body [1][11]. A group of Great Dane puppies had grey to yellow scale and deep skin folds on the head and legs [9].
- Itch: in the more severe forms, yeast overgrowth and hair follicle infection can make the skin itchy, which can be mistaken for allergy [1].
- Eyes in Cavalier King Charles Spaniels: in a syndrome of this breed, puppies are born with a rough, curly coat and have dry eye (KCS) as soon as their eyes open [8]. See our post on eye discharge and red eyes in dogs.
Signs usually start before one year of age, although some dogs first show them as adults [1][6]. In Golden Retriever puppies, a scaling condition breeders call “milk crust” was studied as a possible short-lived form of the breed’s ichthyosis [7].
How it is diagnosed
Because primary ichthyosis cannot be cured, a review stresses working through the possible causes step by step to reach the right diagnosis [3]. In practice your vet:
- looks for the common causes of scaling first, such as allergies, parasites and hormone or metabolic disease [1][3];
- checks for bacterial and yeast infection on the skin [1][3];
- may take a skin biopsy: the handbook says the findings support the diagnosis and help rule out other diseases, though they are often not specific [1][5][6][9];
- may suggest a DNA test where one exists for the breed [1][12].
Your vet chooses the tests for your dog.
Treatment and care
The handbook says the aim is to control the scale, help the skin barrier work better and cut down on infections, with care tailored to each dog [1]. A review likewise describes care on the skin surface plus close follow-up for bacterial and yeast infections [3]. In practice this can include:
- soaks and medicated baths that loosen scale, and moisturising products, as directed by a vet [1][2];
- treating skin infections when they occur, as your vet prescribes [1][3];
- avoiding harsh products that could damage the skin barrier further [1];
- regular rechecks, since care is lifelong [1].
See our posts on pyoderma in dogs and Malassezia yeast skin infection. Do not use human skin medicines on your dog unless your vet tells you to.
Outlook
There is no cure [1][3]. The handbook calls the long-term outlook guarded to poor, mainly because care is needed for life, not because the scale cannot be managed. Severe forms, such as the one in Great Danes, carry a poor quality of life [1]. Outcomes vary between studies:
- In 46 Golden Retrievers diagnosed by skin samples, 22 had signs before 1 year of age, 3 between 1 and 2 years, 13 only after 2 years, and for 8 the age was not known [6].
- In a study of Golden Retriever puppies with “milk crust”, 23 of 28 (82%) did not go on to show typical ichthyosis by one year later, while 5 (18%) still had mild scale [7].
- In Cavalier King Charles Spaniels with the eye and skin syndrome, the report followed dogs for between 9 months and 13 years [8].
These are figures and statements about groups of dogs in particular studies. They do not prove that a treatment caused an outcome, and they cannot predict how one dog will do. Your vet can explain what this means for your dog.
When to see your vet
See your vet if your dog has:
- scaling that does not settle, or large flakes that come off in sheets [1];
- thickened paw pads, or signs of sore feet [1][2];
- red, darkened or rough skin [1][5][10];
- itchy skin or signs of skin infection [1][3];
- a puppy with a scaly coat plus eye discharge or red eyes [8].
FAQ
Will my dog grow out of it?
No one can promise it. See Outlook above for what studies report, and ask your vet what to expect for your dog.
Is it painful?
Thick paw pads can make walking uncomfortable, and yeast or bacterial infections can make the skin itchy [1][3]. Your vet can help keep your dog comfortable.
Is it contagious?
Ichthyosis is described as an inherited condition [1][2], not one that dogs catch from each other. Skin infections that develop on top of it still need a vet [3].
Can cats get it?
This article covers dogs. If your cat has scaly skin, ask your vet.
The bottom line
Ichthyosis is a group of inherited conditions that cause heavy scaling, seen in several dog breeds [1][2]. Most scaly skin has other causes, so your vet looks for those first [3]. Care is lifelong and aimed at the scale and at skin infections, as directed by your vet [1][3].
This article is for general information and does not replace a visit to your veterinarian. If your dog has scaly skin, contact your vet.
Sources
- Torres SMF. 3.3 Ichthyosis: Dogs. Small and Large Animal Dermatology Handbook, Vol. 2. University of Minnesota, 2025. CC BY 4.0. https://open.lib.umn.edu/animaldermatology2/chapter/hereditary-keratinization-disorders-ichthyosis-dogs/
- Torres SMF. 3.2 Hereditary Keratinization Disorders: General Considerations. Small and Large Animal Dermatology Handbook, Vol. 2. University of Minnesota, 2025. CC BY 4.0. https://open.lib.umn.edu/animaldermatology2/chapter/2-hereditary-keratinization-disorders-general-considerations/
- Mauldin EA. Canine ichthyosis and related disorders of cornification. Vet Clin North Am Small Anim Pract. 2013;43(1):89-97. https://pubmed.ncbi.nlm.nih.gov/23182326/
- Mauldin EA, Elias PM. Ichthyosis and hereditary cornification disorders in dogs. Vet Dermatol. 2021;32(6):567-e154. https://pubmed.ncbi.nlm.nih.gov/34796560/
- Guaguere E, Bensignor E, Küry S, et al. Clinical, histopathological and genetic data of ichthyosis in the golden retriever: a prospective study. J Small Anim Pract. 2009;50(5):227-235. https://pubmed.ncbi.nlm.nih.gov/19413748/
- Mauldin EA, Credille KM, Dunstan RW, Casal ML. The clinical and morphologic features of nonepidermolytic ichthyosis in the golden retriever. Vet Pathol. 2008;45(2):174-180. https://pubmed.ncbi.nlm.nih.gov/18424829/
- Roethig A, Schildt KJ, Welle MM, et al. Is “milk crust” a transient form of golden retriever ichthyosis? Vet Dermatol. 2015;26(4):265-e57. https://pubmed.ncbi.nlm.nih.gov/26178606/
- Hartley C, Donaldson D, Smith KC, et al. Congenital keratoconjunctivitis sicca and ichthyosiform dermatosis in 25 Cavalier King Charles spaniel dogs. Part I: clinical signs, histopathology, and inheritance. Vet Ophthalmol. 2012;15(5):315-326. https://pubmed.ncbi.nlm.nih.gov/22212237/
- Hoffmann A, Metzger J, Wöhlke A, et al. Congenital Ichthyosis in 14 Great Dane Puppies With a New Presentation. Vet Pathol. 2016;53(3):614-620. https://pubmed.ncbi.nlm.nih.gov/26242581/
- Casal ML, Wang P, Mauldin EA, et al. A Defect in NIPAL4 Is Associated with Autosomal Recessive Congenital Ichthyosis in American Bulldogs. PLoS One. 2017;12(1):e0170708. https://pubmed.ncbi.nlm.nih.gov/28122049/
- Credille KM, Minor JS, Barnhart KF, et al. Transglutaminase 1-deficient recessive lamellar ichthyosis associated with a LINE-1 insertion in Jack Russell terrier dogs. Br J Dermatol. 2009;161(2):265-272. https://pubmed.ncbi.nlm.nih.gov/19438474/
- De Iorio MG, Polli M, Ghilardi S, et al. Prevalence and genotypic distribution of non-epidermolytic ichthyosis in Italian Golden Retrievers. PLoS One. 2026;21(3):e0345595. https://pubmed.ncbi.nlm.nih.gov/41875098/