What Is Lupoid Onychodystrophy in Dogs?
Lupoid onychodystrophy, also known as symmetrical lupoid onychitis (SLO), is a relatively rare medical condition impacting a dog’s toenails. Typically, it manifests rapidly, affecting all four feet and multiple nails. The nails become dry, brittle, crack, split, and may eventually deform or fall off. When a nail falls off, it exposes the “quick,” causing discomfort and potentially leading to secondary infections.
Dogs afflicted with this condition often exhibit frequent licking of their feet and may experience difficulty walking. While the exact cause is not fully understood, it is believed to stem from an overactive immune response and is not contagious. Furthermore, it is recognized as a genetic condition inherited from one or both parents. Although primarily observed in young to middle-aged dogs between 2–8 years old, it can also affect puppies and senior dogs. German Shepherds, Rottweilers, and Gordon Setters are among the most commonly affected breeds.
Prompt treatment is essential to manage any associated infections. Pet owners should promptly seek veterinary attention if they notice any abnormalities in their dog’s toenails or observe excessive paw licking.
Symptoms
The onset of nail issues initiates from the nailbed, resulting in abnormal nail growth. Typically, the initial signs are indicators of pain—excessive licking of the paws or limping and lameness. Subsequently, the affected nail lifts off the nailbed, eventually falling off and exposing the sensitive tissue beneath. Initially, one or two nails may be lost, followed by the shedding of all nails over a span of weeks or months. Due to the discomfort associated with this condition, dogs may resist having their feet examined. Dogs suffering from SLO generally maintain overall good health, although some cases may lead to enlarged lymph nodes (lymphadenopathy).
Secondary nail bed infections may arise due to this disease, leading to redness and swelling of the toes, accompanied by an odor or discharge. Often, these infections stem from bacteria encountered by the exposed nail bed from the ground.
Affected nails typically exhibit the following characteristics:
- Splitting or cracking
- Brittleness
- Thickening
- Deformation
- Presence of pus and/or blood underneath
- Abnormal curvature
Causes
The precise cause of lupoid onychodystrophy in dogs remains uncertain, yet it is believed to stem from an immune-mediated condition with a genetic predisposition. SLO stands as the predominant immune-mediated ailment leading to abnormal nails and eventual nail loss.
Diagnosis
Veterinarians may initially consider a presumptive diagnosis of SLO based on the appearance of the toenails and the dog’s medical history. However, they typically aim to exclude other potential causes such as bacterial or yeast infections, ringworm, and certain types of cancers.
To differentiate, a culture of the affected nail can eliminate possibilities of bacterial, fungal, or ringworm infections. X-rays are also essential to assess the health of the underlying bone and to rule out any signs of cancer. Ultimately, a biopsy of the nailbed or a fine needle aspirate is performed to examine the cells, a procedure known as histopathology or cytology.
In severe cases of nail bed lesions, veterinarians may opt for digit amputation at the dewclaw for biopsy purposes. It’s important to note that the fallen-off nail itself does not provide a diagnosis; examination of the nailbed is imperative. These diagnostic tests should confirm the presence of SLO if the dog is indeed affected.
Treatment
Various treatment options exist for dogs affected by SLO. Unfortunately, a standardized treatment regimen for this uncommon condition has not yet been established. The primary focus of treatment is on immune system suppression. Improvement in toenail condition typically begins within six to 12 weeks of treatment initiation. Medications may require initial adjustments, but the most effective ones identified by the veterinarian are typically administered for life.
Commonly prescribed medications, supplements, and treatments include:
- Fatty acids, particularly EPA and DHA found in fish oils, which constitute a fundamental aspect of treatment.
- Immunosuppressants like Cyclosporine and Azathioprine.
- Prednisone or other corticosteroids are used initially for severe cases but are not typically prescribed for long-term use.
- Pentoxifylline, which suppresses inflammatory responses.
- Vitamin E supplementation.
- Tetracycline or Doxycycline combined with niacinamide (vitamin B3).
- Regular nail trims.
- Antibiotics to address secondary bacterial infections.
For severe or recurrent instances of SLO, more aggressive treatment approaches may be necessary, including onychectomy, which involves the surgical removal of the toe tip. This procedure is typically performed using a laser or a scalpel blade. However, onychectomy is not commonly undertaken unless there is significant unmanageable pain and nail bed deformity.
Living and Management
The overall prognosis following treatment for SLO is generally favorable, although nails may remain prone to breakage and deformity. Clinical improvement with successful therapy typically becomes noticeable within three to four months.
It is crucial to adhere strictly to the prescribed medications and supplements provided by your veterinarian. Avoid discontinuing any treatment without their approval, even if you suspect it may not be effective, as relapses can occur.
Regular nail trims are of utmost importance and should be performed every one to two weeks throughout your dog’s life. In certain cases, veterinarians may gradually reduce medication dosage after six months of successful treatment, but long-term administration is usually necessary.
Maintaining cleanliness and dryness of your dog’s paws and toes is beneficial, and using a medicated wipe after outdoor walks is advisable.