Home » Diseases » In dogs » Symmetric Lupoid Onychodystrophy, SLO (Nail and Nail Bed Disease)

Symmetric Lupoid Onychodystrophy, SLO (Nail and Nail Bed Disease) in Dogs

Occurrence: very rare
Location of illness: Legs, Skin/Fur

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Symmetric Lupoid Onychodystrophy (SLO) is an immune-mediated disease in dogs that affects the nails and nail bed, leading to abnormal nail development.

The most important facts at a glance

Symmetric Lupoid Onychodystrophy (SLO) is an autoimmune disease in dogs in which the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. mistakenly attacks the nail bed, which can lead to Inflammatory conditions and the loss of claws. The causes of SLO are still unclear, but genetic factors play a significant role, as certain breeds such as German Shepherds and Setters are more susceptible. Environmental factors such as stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being., infections, and diet may also influence the onset of the disease. Typical symptoms are Licking of the paws, Lameness, Pain, Swelling, and altered horn quality of the claws.

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made by clinical examination and medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits., as well as possible biopsies or blood tests to rule out other diseases. Treatment requires a combination of anti-inflammatory fatty acids, immunosuppressants, and possibly antibiotics to treat secondary infections. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends on the severity of the disease and the response to treatment, with many dogs able to lead a normal life with timely therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. Preventive measures are difficult because the exact causes are not fully known, but a balanced diet and a stress-free environment may reduce the risk. Regular veterinary examinations are particularly important in susceptible breeds to detect and treat the disease early.

Causes

Symmetric Lupoid Onychodystrophy is a specific form of onychodystrophy, a condition that affects the structure and growth of the nails. In SLO, it is an autoimmune disease in which the dog’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. mistakenly attacks the body’s own tissue of the nail bed. This immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. defense reaction leads to chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Inflammatory conditions, which weaken the structure of the nails and can cause them to fall off.

The exact cause of SLO is not yet fully understood, but genetic factors play a crucial role. Certain dog breeds such as German Shepherds, Setters, and Dachshunds appear to be predisposed. It is believed that a combination of genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. and environmental factors, such as stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. or infections, can triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. the onset of the disease.

Some researchers suspect that environmental factors such as diet, contact with certain chemicals, or even the general health of the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. may play a role. In addition, reduced blood flow to the nail bed could contribute to the development of the disease by allowing the body’s defense mechanisms easier access to the nail structures.

Symptoms

Very common symptoms:

Common symptoms:

Claws with Altered Horn Quality (Dry, Brittle, Deformed, Shortened, Rough, Soft)

Dogs with Symmetric Lupoid Onychodystrophy typically show symptoms that are mainly limited to the nails and nail bed. A common sign is the sudden loss of nails. This can affect one nail or several nails at the same time. The nails can become brittle, split, or become deformed. Often the affected nails are painful, and the dog may show signs of discomfort or Pain when walking.

In addition, redness, Swelling, and Inflammatory condition of the nail bed can occur. These symptoms can be accompanied by a bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., especially if the nails are damaged and the underlying tissue is exposed. In some cases, there may be a foul odor indicating a secondary infectionA secondary infection occurs when an already weakened individual suffers an additional infection, often because the immune system is impaired by the primary infection..

Frequently, dogs lick or chew on their paws to relieve the Pain, which further increases the risk of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. In severe cases, the disease can significantly affect the dog’s normal life, as the Pain when walking or standing can lead to reduced mobility.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of Symmetric Lupoid Onychodystrophy is primarily based on the clinical examination and the dog’s medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits.. An experienced veterinarian will closely examine the symptoms, especially the changes in the nails. The historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. of sudden nail loss and the breed of the dog can provide important clues.

To rule out other causes of nail disease, additional tests may be required. A biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions. of the nail bed can be performed to confirm the presence of inflammatory cells and to rule out other conditions such as fungal infections or Tumors. Blood tests can also be helpful to assess the dog’s general health and rule out other autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus..

In some cases, an X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. of the paws may also be necessary to rule out structural damage to the bones or joints that could potentially lead to similar symptoms.

Therapy

Treatment for Symmetric Lupoid Onychodystrophy requires a multidisciplinary approach and aims to alleviate symptoms and modulate the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. A commonly used treatment method is the administration of fatty acids, which have anti-inflammatory properties. Omega-3 and omega-6 fatty acids can be given in the form of supplements to reduce inflammatory conditions and support nail health.

In more severe cases, the veterinarian may prescribe immunosuppressants such as corticosteroidsCorticosteroids are a class of steroid hormones that occur naturally in the body and can also be produced synthetically. They have anti-inflammatory and immunosuppressive properties and are used in veterinary medicine to treat a variety of conditions. or other immunomodulatoryImmunomodulatory describes the ability of a substance to modify the reaction of the immune system. Immunomodulatory drugs can either stimulate the immune system to fight infections more effectively or suppress it to prevent overreactions. drugs to suppress the overactive immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens.. These medications must be carefully dosed and monitored to minimize side effects.

Antibiotics may be needed to treat secondary infections, especially if there are open Wounds or detached nails. Regular paw care and nail trimming are also important parts of therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. to avoid complications.

Prognosis and follow-up care

The prognosis for dogs with Symmetric Lupoid Onychodystrophy varies depending on the severity of the disease and the response to treatment. With timely diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and appropriate therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions., the disease can often be successfully controlled, although it is rarely completely cured. Many dogs show a significant improvement in symptoms with consistent treatment and can lead a normal, Pain-free life.

In some cases, the disease can become chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time., with periods of remission and relapse. Careful monitoring and adjustment of treatment is crucial to achieve the best possible outcome.

Prevention

Since the exact causes of Symmetric Lupoid Onychodystrophy are not yet fully understood, there are no specific preventive measures. However, a balanced diet rich in essential fatty acids can support the dog’s general health and potentially reduce the risk of the disease.

It is important to carry out regular veterinary examinations, especially in breeds that are predisposed to the disease. Early detection and treatment can help to slow the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease and improve the dog’s quality of life.

Avoiding stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. and a healthy environment can also help to reduce the risk of autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus.. Dog owners should ensure that their animals are not unnecessarily exposed to chemicals or other potential triggers.

Outlook on current research

Symmetric Lupoid Onychodystrophy (SLO) is a relatively rare disease that mainly occurs in dogs and is characterized by the loss of claws, Pain, and Inflammatory conditions. Although the exact cause of SLO is not yet fully understood, it is believed to be an autoimmune disease in which the dog’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. attacks its own claws.

Current research focuses on the genetic and immunological factors that may contribute to the development of SLO. Scientists are investigating the role of genetic predispositions and trying to find out if certain breeds are more susceptible to developing SLO. There is evidence that certain dog breeds, such as the German Shepherd, the Gordon Setter, and the Bearded Collie, are more frequently affected, which may indicate a genetic component.

Another focus of research is on the investigation of the immune responses that occur in dogs with SLO. Researchers are working to identify the specific immune cellsImmune cells are specialized cells of the immune system that help to identify and fight pathogens and foreign substances. These include leukocytes such as lymphocytes (T cells and B cells), macrophages, and dendritic cells. and molecules that are involved in the pathogenesisPathogenesis describes the process of the origin and development of a disease, including the mechanisms that lead to the disease's symptoms and signs. of the disease. These findings could lead to the development of new therapeutic approaches that specifically target the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. to alleviate the symptoms of SLO and slow the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease.

In addition, various treatment strategies are being tested in clinical trials, ranging from the administration of omega-3 fatty acids to the use of immunomodulatoryImmunomodulatory describes the ability of a substance to modify the reaction of the immune system. Immunomodulatory drugs can either stimulate the immune system to fight infections more effectively or suppress it to prevent overreactions. drugs. These studies aim to identify the most effective and safest treatment methods for affected dogs. Research in the field of Symmetric Lupoid Onychodystrophy is promising and it is expected that new findings and therapeutic approaches will be available in the near future.

In addition, the influence of environmental factors on the development and course of SLO is being investigated. Factors such as diet, stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being., and exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. to certain chemicals could also play a role and are therefore being considered in current studies. This comprehensive approach to researching SLO will hopefully help to improve the quality of life of affected dogs and possibly develop preventive measures.

Frequently asked questions (FAQs)

What is Symmetric Lupoid Onychodystrophy (SLO)? SLO is an autoimmune disease in dogs that affects the claws. It leads to Pain, Inflammatory conditions, and eventually the loss of the claws.
Which dogs are most often affected by SLO? Certain breeds such as German Shepherds, Gordon Setters, and Bearded Collies are more susceptible to SLO, which suggests genetic factors.
How is SLO diagnosed? The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is usually made by clinical examination and exclusion of other diseases. A biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions. of the nail bed can also be helpful.
What symptoms indicate SLO? Symptoms include redness and Swelling of the nail bed, Pain when walking, peeling or missing claws, and occasionally Lameness.
How is SLO treated? Treatment may include the administration of omega-3 fatty acids, vitaminVitamins are organic compounds that are necessary in small amounts for the normal growth, development, and physiological function of the body. Vitamins must mostly be obtained through food, as the body cannot produce them or not in sufficient quantities. E, and immunomodulatoryImmunomodulatory describes the ability of a substance to modify the reaction of the immune system. Immunomodulatory drugs can either stimulate the immune system to fight infections more effectively or suppress it to prevent overreactions. drugs. The treatment is individually adjusted.
Is SLO curable? SLO is not curable, but the symptoms can be controlled with the right treatment and the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease can be slowed down.
Can environmental factors influence SLO? Yes, environmental factors such as diet and stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can influence the development and course of SLO, which is why a comprehensive investigation of these factors is important.
How can the risk of SLO be reduced in dogs? While genetic factors cannot be changed, a balanced diet, stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. reduction, and regular veterinary check-ups can help to minimize the risk.
Are there new research findings on SLO? Yes, current research focuses on genetic and immunological aspects, the development of new therapeutic approaches, and the investigation of environmental factors.
What should I do if I suspect that my dog has SLO? If you suspect that your dog is suffering from SLO, you should see a veterinarian as soon as possible to obtain an accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment plan.