In dogs, autoimmune skin diseases occur when the immune system mistakenly attacks skin cells. Integrative veterinarian Dr. Julie Buzby discusses the basics of canine autoimmune skin diseases and highlights the predisposed breeds, symptoms, treatment, and prognosis for six different dog autoimmune skin diseases.
If you headed to the vet thinking your dog just had a simple skin infection, had scraped his or her nose, or ripped off a toenail, and then left with a tentative diagnosis of an autoimmune skin disease, you may be feeling a bit like you are in foreign territory. However, learning about canine autoimmune skin conditions can help you navigate that path with your sweet dog.
What are autoimmune skin diseases in dogs?
Autoimmune skin disease is an umbrella term for conditions that occur when the immune system sees normal skin cells as “foreign” and begins to attack them. Depending on the exact disease, the consequences of this attack may include changes in normal skin pigmentation, loss of nails, painful sores, blisters, hair loss, or chronic non-healing wounds.
What causes autoimmune skin diseases in dogs?
Sometimes, there is no apparent underlying cause for the onset of an autoimmune skin disorder. In other cases, genetic predisposition, a recent history of vaccination, exposure to certain toxins (pesticides), environmental stressors (allergens and pollution), and bacterial or viral infections may be enough to trigger the abnormal immune response.
A word about vaccines: Vaccines help your dog’s immune system fight off serious diseases. In very rare cases, this response may trigger autoimmune problems, especially for dogs with other predisposing risk factors. But, for most dogs, the benefits of vaccination far outweigh the risks. Your veterinarian will guide you on which vaccines are best for your dog based on your dog’s medical history and lifestyle.
How does the vet diagnose autoimmune skin diseases?
Canine autoimmune skin disease can be a challenge to diagnose because the symptoms can look like a lot of other disease processes. Thus, reaching a diagnosis involves a combination of ruling out “look-alikes” and performing a skin biopsy to confirm the dog has an autoimmune skin disease.
Tests to rule out other conditions
The vet will need to perform a variety of tests to rule out common parasitic, bacterial, and fungal infections, and certain cancers. Plus, the vet may recommend screening for systemic diseases that cause skin symptoms. This may involve:
- Skin scrapes: Rules out parasites like demodex (the cause of demodectic mange) or scabies (the cause of sarcoptic mange).
- Cytology: Looks for yeast, bacteria, or fungal organisms that point to infection, and specific blood cells like lymphocytes, which may indicate inflammation or the presence of certain types of cancer (like epitheliotropic lymphoma).
- Microscopic examination of hair (trichology): Identifies parasites or fungal spores that may be attached to the hair shaft, establishes the phase of hair growth, and identifies broken hair shafts that might indicate the dog is scratching or chewing at the coat excessively.
- Blood tests for dogs: Helps identify hormonal imbalances like hypothyroidism in dogs or Cushing’s disease in dogs that may affect the skin.
If none of these tests reveal an explanation for the skin problems, or the skin remains abnormal even after addressing an infection, autoimmune disease becomes more and more likely.
Biopsy to confirm an autoimmune skin disease diagnosis
However, definitively diagnosing an autoimmune skin disease requires a skin biopsy in dogs.
The procedure may vary a bit from one location on the body to another, but often the vet will want to take biopsies from several areas. This gives the best chance of reaching a diagnosis. While your dog is under anesthesia, the vet will obtain several small pieces of skin and then send them to the diagnostic lab. There, the veterinary dermatopathologist (pathologist who focuses on interpreting skin biopsies) will evaluate the cells and skin layers.
He or she will be looking for abnormal cells in and around the hair follicle, including inflammatory cells and cancer cells. Plus, the pathologist can detect any overall changes to the skin architecture in the biopsy sample. Based on the dog’s history and what he or she sees on the biopsy, the dermatopathologist will provide an interpretation and diagnosis.
The diagnosis will likely end up being one of the following six autoimmune skin diseases in dogs.
6 autoimmune skin diseases in dogs
Multiple autoimmune conditions can affect a dog’s skin, nose (which is made of specialized skin cells), and/or toenails (which also grow from skin cells). They have different symptoms depending on which skin cells are getting attacked, and the treatment and prognosis can vary, too.
1. Pemphigus complex in dogs
Pemphigus complex is an umbrella term for a group of autoimmune diseases that may develop when the body begins to attack its own skin cells. The different types of pemphigus affect the skin in different ways.
Pemphigus foliaceous (PF)
Pemphigus foliaceous is the most common canine autoimmune skin disease. Not only does PF affect the skin, but it may also have more serious systemic signs for dogs who are not diagnosed quickly.
Breeds predisposed to pemphigus foliaceous include:
- Akitas
- Chow Chows
- Cocker Spaniels
- Dachshunds
- English Bulldogs
- Labrador Retrievers
However, other breeds (and cats) can also be affected by PF.
At first, dogs with pemphigus foliaceous develop large blisters and ulcerated areas of skin around the face and ears. However, if not diagnosed quickly, pemphigus foliaceous can progress to involve the feet, trunk, and groin.
As the blisters begin to rupture, they leave large, eroded lesions and ulcerated sores on the skin. When the scabs peel off, they also remove chunks of fur. This leaves the dog with horribly flaky skin and patchy areas of hair loss.
Systemic effects of this disease include fever, being a lethargic dog, poor appetite, itchy skin, and pain when walking, particularly if the feet are also affected.
PF has a guarded prognosis, and relapses can develop even with long-term treatment.
Pemphigus erythematosus (PE)
Pemphigus erythematosus is a milder form of pemphigus foliaceous. Affected dogs may have redness or crusting on the ears, face, and nose. But usually, the rest of the body is spared. It is most common in German Shepherds, Collies, and Shetland Sheepdogs. Thankfully, PE carries a good long-term prognosis with treatment, although treatment may be necessary for the rest of the dog’s life.
Pemphigus vegetans
Pemphigus vegetans is a rare form of pemphigus. In contrast to the other forms, this condition causes non-painful, wart-like lesions to develop on the skin rather than ulcerations. Typically, dogs will develop pemphigus vegetans lesions on the head and neck, as well as the oral cavity, lips, prepuce, and around the anus.
Pemphigus vulgaris (PV)
The most severe form of pemphigus is pemphigus vulgaris (PV). Usually, the lips and eyes are the first areas to be affected. But, like PF, pemphigus vulgaris can also progress to other areas of the body. PV blisters erupt from deeper layers of the skin, leaving painful ulcerations after they rupture.
Unfortunately, because of its aggressive nature, pemphigus vulgaris generally carries a poor prognosis.
Treatment for pemphigus complex
Treatment of pemphigus disorders involves high doses of steroids and other immunosuppressive medications to calm the immune response and relieve inflammation.
Unfortunately, treatment of pemphigus is not always successful, usually due to side effects of the drugs or a lack of response to therapy. Even if the dog achieves complete remission of symptoms, relapses can occur, and treatment may need to be lifelong.
Especially in severely affected dogs (usually those with the foliaceous or vulgaris form), poor response to treatment or severe clinical signs may lead to euthanasia due to an unacceptable quality of life.
2. Discoid lupus erythematosus (DLE) in dogs
Also known as nasal solar dermatitis or collie nose, discoid lupus erythematosus (DLE in dogs) is an autoimmune skin condition that primarily targets the tissue of the nose. Clinicians believe one reason this disease occurs is excessive exposure to UV radiation, which causes inflammation in the sensitive tissue layers of skin around a dog’s nose and muzzle.
Predisposed breeds include Collies, German Shepherds, Shetland Sheepdogs, and Siberian Huskies.
Initially, symptoms include ulcerated skin and loss of pigmentation on the nose, as well as a change in its normal cobblestone appearance. DLE lesions that cause deep ulcers may also damage local blood vessels on the muzzle and cause bleeding. As the condition worsens, skin lesions may appear around the eyes, lips, ears, and (rarely) the genital area.
Treatment for DLE involves oral and/or topical steroids to dampen the immune response and relieve inflammation. Cyclosporine and tacrolimus ointment can also help suppress the immune system’s need to attack normal cells. Doxycycline (an antibiotic) and niacinamide (a B-vitamin supplement), given in combination, are also highly effective in controlling DLE symptoms.
3. Symmetric Lupoid Onychodystrophy (SLO) in dogs
Symmetric lupoid onychodystrophy (SLO in dogs) is an unusual and uncommon autoimmune disorder that only affects the dog’s toenails and nail beds. Studies have identified a link between SLO and thyroid inflammation (autoimmune thyroiditis). Plus, there may be a hereditary component. Predisposed breeds include Bearded Collies, German Shepherds, Gordon Setters, and Rottweilers.
Symptoms of SLO can be subtle at first, with only one or two nails initially affected. The nails become brittle, crack, and peel away from the underlying nail bed. Dogs with SLO tend to lick their feet excessively and limp when the toes are painful. As the toenails detach from the nail beds and slough off the toe, secondary infections often develop. Over time, SLO can progress to involve the nails on all four feet.
In addition to the diagnostics mentioned earlier, the vet may recommend X-rays of the feet for dogs with suspected SLO. This can help rule out osteomyelitis (bone infections) and osteosarcoma (bone cancer) of the toes.
Treatment of SLO is a slow process, requiring medications to be given for months or sometimes for life. Antibiotics (tetracycline) and vitamin therapy (niacinamide and Vitamin E) are typically the first line of treatment. Additionally, omega-3 fatty acids for dogs and the medication pentoxifylline can be useful in some cases. As a last resort, the vet may recommend surgical amputation of severely affected nails.
Thankfully, dogs with SLO have a good long-term prognosis with early diagnosis and aggressive therapy.
4. Uveodermatological Syndrome (UDS) in dogs
Also known as Vogt-Koyanagi-Harada-like syndrome (similar to the human version of this condition), uveodermatological syndrome is a rare autoimmune condition that develops when the immune system attacks melanocytes (pigment cells) in the eyes, skin, and other heavily pigmented tissues. Young adult dogs are most commonly affected. Interestingly, Akitas make up roughly 75% of all diagnosed cases of UDS.
Symptoms
Typically, dogs will develop symptoms related to the eyes before the skin symptoms start to show up. Some eye-related symptoms include:
- Progressive loss of vision: Bumping into things and other signs of vision loss are usually the first symptoms
- Light sensitivity (photophobia): Squinting in bright lights or not wanting to enter bright areas
- Generalized pain and inflammation: An elevated third eyelid in dogs, tearing, and squinting point to pain
- Cloudy eyes in dogs: The cornea and/or inner structures of the eye may look hazy
- Redness within the eye: Red blood cells may accumulate inside the eyes (hyphema)
- Inflamed eyelids and the whites of the eyes (sclera): Eyes look bloodshot and eyelids are red
- Changes in the appearance of the iris: May look darker or more reddish than normal or change color entirely
Plus, dogs may have dermatological symptoms, including depigmentation of the fur and skin around the mouth, nose, eyes, and genital area. This loss of pigmentation is often bilaterally symmetrical. Affected areas may also be crusty, ulcerated, and have less hair than usual.
Interestingly, humans with UDS also experience neurologic symptoms, but this does not appear to be an issue for dogs.
Diagnosis
Diagnosis of UDS can be challenging due to the wide variety of symptoms. Your vet will consider your dog’s breed, age, physical exam findings, and health history. Eye changes alone may not be diagnostic, so skin biopsies of affected areas can help confirm a diagnosis.
Treatment and prognosis
Treatment typically involves topical drops to relieve eye symptoms and oral prednisone with azathioprine to manage skin symptoms. Like SLO, niacinamide has also shown some benefit for dogs with UDS.
The prognosis for dogs with UDS varies depending on which symptoms are the worst. Early diagnosis and treatment improve the prognosis for both ocular and dermatologic symptoms. However, the prognosis remains guarded to poor in dogs with severe symptoms or in cases where treatment is not initiated immediately after diagnosis.
5. Bullous pemphigoid in dogs
Bullous pemphigoid is a rare condition in dogs in which tiny fluid-filled sacs (bullae) form on the skin. While there isn’t a definitive breed predisposition due to a low number of reported cases, it might be more common in Dachshunds, German Shepherds, and Collies.
Once the skin is under attack, blisters and erosive ulcers appear around the muzzle, armpits, groin, ear flaps (pinnae), and occasionally the toenails and footpads. The blisters tend to grow and rupture quickly, so you may only see ulcerated areas on your dog’s skin. The affected areas seem to be itchy or painful in some dogs, but not others.
The vet may prescribe topical and/or oral steroids or other medications to treat your dog’s bullous pemphigoid lesions. Sometimes treatment needs to be continued long-term, but there have been dogs who were successfully weaned off their medications.
It is also worth noting that dogs with bullous pemphigoid should avoid exposure to high amounts of UV light. This may help prevent worsening of the condition.
6. Alopecia areata in dogs
Alopecia areata (AA) is a relatively rare autoimmune skin disease that triggers the immune system to attack proteins on the bulb of normal hairs, causing those hairs to fall out. Thus, this condition is characterized by patches of hair loss on the head, neck, and legs. Belgian Shepherds, Dachshunds, Doberman Pinschers, and Miniature Pinschers tend to get alopecia areata more commonly.
Typically, dogs with AA will have clinical signs including:
- Focal, patchy areas of hair loss: Usually visible on the head, ear flaps, neck, and legs. Rarely, dogs will also lose their whiskers (vibrissae) and eyelashes.
- Hyperpigmentation: Hairless areas of skin appear darker than the surrounding haired areas because the empty hair follicles become clogged with yellowish-brown, waxy debris.
Interestingly, veterinarians note that dogs with AA are not itchy. This is in contrast to many other common skin diseases that also lead to your dog losing hair.
For treatment, the vet may recommend oral anti-inflammatory medications (such as cyclosporine and/or prednisone) to suppress the overactive immune response. There are mixed opinions about how well these medications work, however. Some studies indicate that immunosuppressive therapy isn’t necessary since many dogs regrow their hair within 6 to 12 months of the onset of AA.
Regardless of whether the vet decides to put your dog on immunosuppressants, melatonin for dogs with hair loss can be beneficial as it may support a normal hair growth cycle. Interestingly, when dogs with AA do regrow their hair, it’s often unpigmented (grey or white).
Work with your veterinarian
As your dog’s biggest advocate, it’s essential to monitor your dog regularly for any unusual symptoms, rashes, or changes in his or her health. If you notice new or worsening skin changes in your sweet dog, schedule a visit with your veterinarian. Then work closely with the veterinary team during the diagnosis and treatment process.
I know it can be scary. But remember, with early care and ongoing support, many dogs with autoimmune skin disease can still enjoy a comfortable, happy life.
Has your dog ever been diagnosed with an autoimmune skin disease?
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