SYMPTOM
Cracked or splitting claws
Owners notice a claw that is cracked, peeling in visible layers, bent at an odd angle, or has come away from the toe entirely, sometimes with bleeding or visible sensitivity when the paw is touched.
Traumatic Nail Injury
A claw snagged on carpet, fencing, or rough ground during normal activity is the most common cause of an acute crack, split, or avulsion, and typically affects a single claw on one paw without symmetry. This carries a straightforward mechanical explanation, and once the immediate injury has settled the claw usually regrows normally over subsequent months. It is more likely in active or outdoor dogs and in cats that catch a claw while jumping or climbing.
Reduced Wear From Inactivity Or Joint Pain
Claws are naturally worn down through contact with hard ground during activity, and a pet that is less active because of joint pain or general ageing can develop overgrown, brittle claws that split more readily under everyday pressure. This pattern tends to affect multiple claws gradually rather than appearing as a single acute injury, and often coincides with a broader reduction in activity level.
Symmetric Lupoid Onychodystrophy
This immune-mediated condition causes claws to become dry, brittle, and to crack, split, or slough away from multiple paws in a roughly symmetrical pattern, typically starting with one or two claws before progressing to involve most or all of them over weeks to months. German Shepherds, Rottweilers, and Gordon Setters are among the breeds more commonly affected, with onset typically between two and six years of age.
Infection Around The Nail Fold
Bacterial or fungal infection at the base of the claw can weaken the nail fold and lead to a claw that becomes misshapen, discoloured, or prone to splitting, often with visible swelling or discharge at the base. This is more likely to affect one or a small cluster of claws rather than being symmetrically distributed.
Subungual Tumour
A mass arising from the nail bed itself, including melanoma or squamous cell carcinoma, can cause a single claw to become deformed, loosen, or fracture repeatedly despite no clear trauma, and is more common in older dogs. This category is distinguished by its persistence in one specific digit over time rather than affecting claws more broadly.
Hypothyroidism
Reduced thyroid hormone in dogs can produce broader skin and coat changes, including claws that become dry, brittle, and prone to splitting, usually alongside other signs such as a dull coat, weight gain, or lethargy rather than as an isolated finding.
Why timing matters
Early observation
A single claw affected after an identifiable incident, such as catching it on furniture or fencing, most often reflects straightforward trauma in its early days and tends to improve steadily as the claw regrows.
Later presentation
Multiple claws becoming involved over subsequent weeks, particularly in a symmetrical pattern across different paws, shifts the picture toward an immune-mediated or systemic process rather than a series of coincidental injuries.
Because a single traumatic claw injury and an early immune-mediated process can look similar at first, watching whether the pattern stays confined to one claw or spreads to involve others over the following weeks is one of the more useful pieces of information available.
Conditions commonly associated
Symmetric Lupoid Onychodystrophy
This immune-mediated condition directly targets the claw-producing tissue, causing brittle, cracking, and sloughing claws across multiple paws in a symmetrical pattern.
Hypothyroidism in Dogs
Reduced thyroid hormone affects skin and claw tissue turnover broadly, producing claws that become dry, brittle, and prone to splitting alongside other coat changes.
Osteoarthritis in Dogs
Reduced activity from joint pain lessens the natural wearing-down of claws through ground contact, allowing them to become overgrown and more prone to splitting.
Pyoderma
Bacterial infection extending to the tissue around the nail fold can weaken claw attachment and lead to a claw becoming misshapen or prone to breaking.
Dermatophytosis (Ringworm)
Fungal infection can involve the claws themselves, producing a brittle, misshapen, or crumbling texture distinct from a traumatic split.
Squamous Cell Carcinoma
A tumour arising from the nail bed can cause a single claw to repeatedly loosen, deform, or fracture despite no clear traumatic cause.
When to explore further
Multiple claws affected in a roughly symmetrical pattern across more than one paw points toward a generalised process rather than a single traumatic event.
One specific claw that repeatedly fractures, becomes misshapen, or fails to regrow normally over successive months, without a clear pattern of trauma, may benefit from closer characterisation.
Swelling, discharge, or an unpleasant odour at the base of a claw suggests an infective component distinct from a simple mechanical split.
Claw changes accompanying a broader pattern of coat dullness, weight change, or reduced energy point toward a systemic rather than purely local explanation.
A claw injury with persistent bleeding, or one where the exposed quick remains visibly raw for more than a few days, adds information about healing progress.
Photographing the affected claw or claws at intervals gives a useful record of whether the pattern is confined to one digit or spreading to others over time. Noting how many claws are affected, on how many paws, and whether the pattern is symmetrical helps distinguish a traumatic explanation from a generalised one. Keeping track of any accompanying coat, weight, or energy changes adds context that a claw finding alone would not capture.
Last reviewed: 12 September 2026 · Dr Alastair Greenway MRCVS