You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Animal claws are composed of horny material derived from the same cells as the epidermis of the skin. The claws are attached to the underlying bone and they are well supplied with blood. Various diseases can involve the claws or nail beds.

There are a variety of abnormal conditions of the claws including :

• Abnormal size of the claws
• Abnormal curvature
• Sloughing of the claws
• Softening of the claws
• Brittleness
• Splitting
• Breaking - may respond to vitamin (biotin) supplementation
• In-growing claws
• Inflammation 
• Pain

Causes of these abnormalities include :

• Trauma (affects one or more toes)
• Infections - bacteria, fungal, leishmaniasis (can be localised to one or affect more than one toe)
• Immune diseases - bullous pemphigoid, pemphigus vulgaris, pemphigus foliaceus, systemic lupus erythematosus. Usually affects most toes
• Nutritional deficiency - usually affects all toes
• Secondary to systemic disease - hypothyroidism, cushings disease, allergy -atopy. (usually affects most toes)
• Reaction to drug therapy (usually affects most toes)
• Cancer - affects one or more toes
• Idiopathic (unknown) causes

Diagnosis of the primary cause is sometimes complex and requires various investigative procedures and laboratory examination of samples.

Dog claws should wear down naturally during exercise, but if they don't they should be kept short and blunt to prevent catching in carpets and undergrowth - especially during vigorous exercise when it is not uncommon for nails to be broken or ripped off.

Cat claws are retractable and so they aren't always kept short by routine exercise. They should be regularly trimmed and kept blunt to prevent catching.

Care is needed when clipping dog and cat nails otherwise the blood vessel that runs down them can be cut accidentally and it will bleed profusely ! This blood vessel can be seen in the top third of the nail in animals with white claws, but it may be impossible to see in animals with black pigmented claws.  Also, if the nail is clipped too high it will be painful, and create resentment in the animal, which may develop foot shyness making it difficult to clip the nails again in the future. When in doubt err on the safe side and leave more claw than you would like.

Claws that don't wear down will grow in circles, and eventually grow in to the animals pad which is very painful and can lead to abscess formation.

Treatment depends upon the cause, but sometimes removal of the claw is necessary to get an infection resolved. Providing the nail bed has not been damaged the claw should grow back normally after it has been removed.

Updated October 2013