Hi Nuala
If a dog already has on AI disease then it is known that they are genetically predisposed and this means that it is possible they can get different AI disease. If the damaged nails are on one foot and none of the others are affected then it could be a trauma. Only time will tell because if it is SLO then others will appear and on different feet. This can take months to show. I'm not sure if the information below is in the files but I have pasted it here for convenience. It's an extract from my seminar notes and I hope it is useful.
Jo
SLO comes under the heading of an autoimmune skin disease.
Definition:
Symmetrical: Affecting corresponding parts simultaneously and similarly.
Lupoid: Comes from the word lupus meaning any of a group of skin diseases in which the lesions are characteristically eroded.
Onychodystrophy: Abnormal claw formation.
As previously stated, SLO can be `primary’ or `secondary’, meaning it can occur in isolation, i.e. primary, or it can be secondary to another autoimmune disease such as, pemphigus skin disease; or SLE, a multi-systemic autoimmune disease which is far more serious.
Unlike some autoimmune diseases primary SLO is not life threatening, but it is a very painful and miserable condition until correct treatment is well under way. Primary SLO involves the nails and surrounding area of the feet only. Multiple nails on different feet are always affected but this can take many months to fully develop. Routine blood results are normal in a dog with primary SLO. A dog with secondary SLO would show other signs of being unwell eg., footpads can be affected and other areas of skin involved, very high temperature, lameness, anaemia etc......
Differential Diagnoses
In addition to SLO being linked to other autoimmune diseases, nail disorders can be caused by:
• Trauma (very unlikely that all claws would be involved)
• Infection – bacterial, fungal (again, very unlikely that all claws would be involved)
• Endocrine problems: (eg., resulting from an underactive thyroid or Cushing’s syndrome)
• Nutritional causes
If the reason for sloughing nails were due to any of the above, other than trauma or infection, it is likely that other clinical signs would be evident.
Wrong Diagnosis
Initially only one or two nails are affected. It’s common, and not unreasonable, for the vet to assume a diagnosis of bacterial or fungal infection and treat accordingly. Treatment can go on for several months before both the vet and owner accept that the treatment is not working. The longer SLO is left without appropriate treatment the more nails will become affected. Secondary infection is very likely because the feet are in contact with the ground and the dog will naturally lick his sore feet which may also cause infection.
The first thing you may notice if your dog has a nail problem is when he cries out in pain and limps, or licks his foot. Nails can bleed profusely and this can be alarming to start with. It is natural to think that he has caught his nail on something that perhaps has broken it and made it bleed. It is probably not until a second and maybe a third nail becomes a problem that you might start to connect the two and wonder if this is more than just accidental damage of a couple of broken nails. Of course, one lost nail may be due to trauma or even an infection but if the problem extends to other nails on different feet then it could be SLO.
Clinical signs of SLO can include:
• Lameness, swollen toes.
• Loss or partial loss of nails, licking of feet.
• Bleeding and/or discharge from the nail or surrounding skin.
• Deformity caused by abnormal growth.
• Secondary infection.
• The dog is generally well but may be depressed due to pain.
The disease is progressive and it can take months before all claws are affected. Blood tests will be unremarkable but a full blood test is essential to first rule out the possibility of an underlying disease.