Ichthyosis in Dogs: Symptoms and Treatment

Written and verified by the biologist Samuel Sanchez

Last update: 22 December, 2022

The skin is our body’s first biological barrier. Not only does it protect us from infections and parasites, but it also allows for the regulation of gases and fluids in our bodies. Therefore, conditions that affect the skin are often very harmful and cause various symptoms in affected animals. Ichthyosis in dogs is a clear example of this.

This congenital disease is extremely rare, but it’s worth knowing about because of the possible side effects and the difficulty in treating it. If you want to know more about ichthyosis in dogs and how to detect it before it’s too late, read on.

What is ichthyosis?

The term ichthyosis refers to an epidermal condition of the skin that occurs in dogs due to an inheritable, recessive mutation. Simply put, the disease is encoded in the dog’s DNA and doesn’t occur due to any contact with an external agent (such as a virus, bacteria, or fungus).

As indicated by professional sources, the symptoms of this condition derive from the malformation of the stratum corneum, the outermost layer of the epidermis of the animal. The animal’s skin will appear crusty (hence its name, which can also be known as fish scale disease), show abnormal pigmentation, and even thicken in a pathological way.

Ichthyosis is a genetic disease. Certain breeds are much more predisposed than others to suffer from it.

Types

Canine ichthyosis can be differentiated into several subtypes. These are as follows:

• General ichthyosis: This is a very rare variant of a hereditary nature. Its diagnosis can be made only by observing the patient’s symptoms.
• Epidermolytic: This manifests with characteristic blisters on the skin and occurs at an early age. A skin biopsy is required to make the diagnosis.
• Non-epidermolytic: This is breed-specific and has an autosomal recessive inheritance pattern.

Causes of ichthyosis in dogs

As we stated earlier, ichthyosis is an autosomal recessive type disease in dogs. This means that the causal mutation is on a non-sex chromosome and that, in order to occur, it must be present in both alleles that make up the gene of the animal (the father and the mother).

This condition has been studied extensively in the Golden Retriever to find the exact gene in which the mutation occurs: PNPLA1. If we think of the non-mutated allele as the letter (N) and the ichthyosis-causing allele as (ict), the genetic explanation of the disease is as follows:

1. Dogs (N/N). These are dogs with healthy maternal and paternal alleles; they don’t carry the pathology in their genome and aren’t diseased.
2. Dogs (N/ict). These have one mutated allele and one normal allele. As the condition is recessive, they’re carriers and don’t have ichthyosis. If both parents have this genotype, the offspring will be born with the condition in 25% of the cases and healthy in the remaining 75%.
3. Dogs (ict/ict). These have the mutation in both alleles. Therefore, they develop the disease in all cases.

Beyond the Golden Retriever, breeds such as the Jack Russell Terrier, the Yorkshire Terrier, and the Doberman have a certain predisposition to develop ichthyosis. The best prevention method to avoid it appearing in a canine lineage is to never cross a canine carrying the mutated gene (even if asymptomatic).

In other breeds, the inheritance pattern is much less clear.

Symptoms

The symptomatology of this condition is very specific. Although it may resemble other dermatological diseases (dermatitis, hyperkeratosis, and more), it has a number of unique features. We’ll highlight the following symptoms in canines with ichthyosis:

• Scaly skin
• Excessive dandruff production
• Thickening of the paw pads and other structures. These symptoms are included under the term hyperkeratosis.
• Greasy, hard crusty areas
• A scruffy appearance
• Pain and inflammation in extreme cases, especially on the pads.

Dogs are born with this condition (in its typical variant) and tend to worsen over time. It’s imperative to see a veterinarian at the appearance of any of the above signs.

Diagnosis

The difficulty of diagnosing ichthyosis in dogs depends on the variant that the patient has. Dogs that have just started to show symptoms may be a little more difficult to diagnose, but in almost all cases the disease will be confirmed by physical examination alone. As mentioned above, the symptoms of this condition are unique.

To confirm and be on the safe side, the veterinarian will collect a superficial sample of the dog’s skin to examine under a microscope. This will rule out the presence of mites, fungi, or bacteria that can cause similar lesions. The DNA test (OCT-A type) will be the last step to detect the disease unequivocally.

Treatment of ichthyosis in dogs

Unfortunately, there’s no treatment to cure this condition. It’s a genetic problem and can’t be remedied in any way. However, you can take into account a number of tips and precautions to prevent the animal from worsening or suffering more than necessary. We have selected the following guidelines:

1. Regular combing: Cleaning your dog with a comb and a specific solution (prescribed by the vet) will help you to get rid of the scabs before they harden and cause itching in the animal. You have to be constant and patient.
2. Chemical compounds for home use: Anti-seborrhoeic shampoos can help your dog’s body to produce fewer lipid substances at a skin level during the disease.
3. Medications: Topical use of synthetic retinoids seems to alleviate a dog’s symptoms, but these drugs have a number of reported side effects. Talk to your veterinarian before medicating your dog, especially if they’re in a delicate state of health.

Unfortunately, some dogs develop such a serious condition that they must be euthanized for their own good before they die due to a derived infection. However, it isn’t usually necessary to take such drastic measures.

This disease is chronic and incurable, so it requires constant attention from the owner. Without a doubt, the best prevention method is not to cross with a specimen that has ichthyosis (or one of the mutated alleles). This is the only way to prevent more dogs from being born with the disease in the long term.