What Are The Symptoms Of Lupoid Onychodystrophy In Dogs?

Lupoid onychodystrophy, also called symmetric lupoid onychodystrophy (SLO) or lupoid onychitis, is an autoimmune disease that affects a dog’s toenails or claws. It is characterized by excessive nail wear, distortions, and sloughing due to an abnormality in nail keratinization.

With lupoid onychodystrophy, the dog’s immune system attacks its own nail beds, leading to inflammation and damage. The nails become rough, brittle, misshapen, overgrown and can even slough off entirely. This is a chronic condition that progresses over time if left untreated.

Lupoid onychodystrophy is considered relatively uncommon in dogs. It occurs more frequently in certain breeds like the Gordon setter, Irish setter, Giant schnauzer, Rottweiler, Portuguese water dog, boxer, Labrador retriever, and German shepherd 1.


Lupoid onychodystrophy is considered an autoimmune disorder, meaning it is caused by the dog’s immune system attacking its own body tissues. The exact cause is unknown, but it appears to involve an abnormal immune response directed against the dog’s nails and surrounding tissue.

While the underlying trigger for this abnormal immune response is unclear, some potential factors that may be involved include:

  • Genetics – certain breeds like Gordon Setters seem predisposed, suggesting a genetic component.
  • Infections – bacterial or viral infections may initiate or exacerbate the immune disorder.
  • Drug reactions – reactions to certain medications like sulfonamides.
  • Cancer – in rare cases, an underlying cancer may provoke an immune response.
  • Allergies – allergic reactions may play a role in some cases.
  • Trauma – physical trauma to nails may initiate the immune reaction.

While these factors may influence the development of lupoid onychodystrophy, the exact pathological process remains unknown. More research is still needed on what triggers the abnormal autoimmune response against the nails in affected dogs.


The most common symptoms of lupoid onychodystrophy in dogs include:

Brittle, malformed nails – The nails become brittle, misshapen, and crumbly. This occurs as the disease damages the nail bed.

Nail loss – Over time, affected nails will lift up and eventually fall off as the disease progresses. This may start with just one nail but eventually affects multiple nails.

Pain and sensitivity – Dogs will often excessively lick at their paws and nails due to pain and sensitivity from the disease. They may also limp or avoid putting pressure on affected nails.

Swelling and redness around nails – The area around affected nails can become inflamed, swollen and reddened as the tissue becomes irritated. This contributes to discomfort and pain.

In the early stages, these symptoms may only affect one nail. But lupoid onychodystrophy often spreads to involve multiple nails on multiple feet over time. Symptoms worsen progressively if the disease is left untreated.

Affected Areas

Lupoid onychodystrophy primarily affects the nails on a dog’s front paws (PetMD). The nails become brittle and cracked, and the nail beds are inflamed. Eventually the nails may slough off entirely in a process called onychomadesis. While the front paws tend to be impacted first and most severely, the nails on the back paws can also be affected as the condition progresses (VIN).

The symmetrical nature of lupoid onychodystrophy means that nails on both front paws and/or both back paws tend to be impacted at the same time. So there is frequently matching nail damage on opposite paws. This helps distinguish lupoid onychodystrophy from trauma-related nail injuries that would likely only impact one paw.


To diagnose lupoid onychodystrophy, the veterinarian will begin with a thorough physical exam of the dog’s claws, looking for key signs like nail loss and claw inflammation. They will also take the dog’s full medical history.

Other potential causes for the symptoms will be ruled out, like bacterial or fungal infections, autoimmune diseases, trauma, and allergies. Claw infections and ringworm may be evaluated using a nail culture. Microscopic examination can check for yeast and bacteria.

According to veterinary partner [1], a biopsy of the nailbed tissue may be taken. This involves surgically removing the nail and examining the tissue beneath it. Biopsy results showing characteristic immune complex vasculitis confirm a diagnosis of lupoid onychodystrophy.

Veterinary clinics like MedVet [3] note that cytology looking at immune cells can also be used to aid diagnosis.

[1] https://veterinarypartner.vin.com/doc/?id=9767513&pid=19239

[3] https://www.medvet.com/lupoid-onychodystrophy-in-dogs/


The main treatment for lupoid onychodystrophy involves suppressing the dog’s overactive immune system to stop it from attacking the tissues of the toenails. Some common immunosuppressive medications used include:1

  • Tetracycline antibiotics like doxycycline, which have immunosuppressive effects
  • Pentoxifylline to improve blood flow
  • Niacinamide (vitamin B3) to reduce inflammation

Vets may also prescribe pain medications like NSAIDs to relieve discomfort during flare ups. Topical therapies like fatty acids and vitamin E applied directly to the nails can help nourish tissues and reduce inflammation.2

Treatment is often lifelong to keep the condition under control. Close monitoring and consistency are important, as stopping medications could lead to recurrence of symptoms.


The prognosis for dogs with lupoid onychodystrophy is variable and unpredictable. The condition tends to have a waxing and waning course, with periods of remission and relapse. According to Veterinary Partner, some dogs may have one or two episodes and never relapse, while others will have chronic nail problems throughout their lives.

Because the root cause is an abnormal immune response, lupoid onychodystrophy requires lifelong management. With consistent treatment, most dogs have improved nail and paw pad quality. However, the nails often remain fragile and prone to cracking. Recurrence of symptoms is common if medications are discontinued. Overall prognosis is good with appropriate long-term treatment and nail care.


There is no known way to prevent lupoid onychodystrophy in dogs. However, avoiding potential triggers may help reduce the risk of flare-ups in dogs already diagnosed with the condition.

Some tips for prevention include:

  • Avoiding trauma or injury to the nails and paw pads.
  • Keeping the dog’s nails trimmed to prevent cracking and splitting.
  • Using ramps and runner rugs to protect the nails.
  • Keeping the dog at a healthy weight to reduce stress on the joints and nails.
  • Feeding a balanced diet rich in antioxidants.
  • Avoiding exposure to extreme cold or dampness.
  • Reducing stress and anxiety which may exacerbate the condition.

While lupoid onychodystrophy itself cannot be prevented, taking steps to promote nail health and reduce potential triggers may help affected dogs manage the condition.

Lifestyle Impact

Lupoid onychodystrophy can have a significant impact on a dog’s lifestyle and quality of life. The most notable effects are pain, discomfort, and difficulty walking.

The cracking, deformity, and fragility of the toenails causes significant pain. Dogs will often lick at their paws excessively in an attempt to alleviate this discomfort. This can lead to secondary infections. The pain also causes dogs to become reluctant to walk or exercise.

The structural abnormalities of the toenails make walking normally very difficult. The nails are unable to bear weight properly. Jagged nail edges put pressure on the paw pads. This leads to altered gait and limping. Dogs may avoid standing or walking for prolonged periods.

All of these factors mean dogs are less willing and able to be active. Simple activities like going for walks, playing, or going up and down stairs become challenging. This can lead to frustration, anxiety, and depression. Treatment is aimed at restoring normal nail structure and eliminating pain so dogs can resume their usual active lifestyles.

When to See a Vet

It’s important to take your dog to the vet if you notice any signs of lupoid onychodystrophy. Some key signs to watch for include:

Visible nail damage – Lupoid onychodystrophy causes the nails to become misshapen, discolored, brittle, and cracked. Any abnormal changes to the nails could signal the disease.

Signs of pain or discomfort – Dogs with lupoid onychodystrophy may lick at their paws, limp, or avoid bearing weight on their feet because of the nail pain and damage. These are signs to get prompt veterinary attention.

Any swelling around nails – Inflammation around the nail beds or nail folds is common with lupoid onychodystrophy. Sudden swelling is a reason to have your dog seen.

Early diagnosis and treatment is key to managing lupoid onychodystrophy. At the first signs of nail issues, it’s advisable to schedule a veterinary exam. Your vet can run tests to confirm the diagnosis and start appropriate treatment to get your dog’s nails healing and relieve any discomfort.

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