Do You Do the Dew?

What is a dewclaw?

Almost all dogs are born with five claws, or toenails, on each front paw. Four of the claws extend from the toe pads on the front of the paw. The fifth claw, the dewclaw, sits above the wrist. It gets its name because its position on the leg is high enough above the ground that it only brushes the morning dew.

Claws are like human fingernails in that they are composed of keratin and contain nerve endings and blood vessels. They provide traction when the dog is moving and are used for digging or holding objects such as a bone or prey. The paw-and-claw combination resembles the human hand and fingers, with the dewclaw functioning as the thumb.

It is believed that the dewclaw stabilizes the leg, improves traction and enables manipulation of the feet. Dewclaws do not touch the ground when the dog is standing still, but when dogs are running at full speed, the dewclaws are in contact with the ground.

Some breeds use their dewclaws to navigate rough environmental conditions. The Beauceron, the Great Pyrenees and the Icelandic Sheepdog use their dewclaws for gaining traction on ice in slippery winter weather. Retrievers working on ice while fetching late-season ducks are likely to use their dewclaws too for better grip on their footing. Upland hunting breeds that perform pointing and flushing tasks use their dewclaws for improved traction when climbing hillsides and rough terrain.

Some herding or guarding breeds have double dewclaws. The Great Pyrenees, Briard, Beauceron and Icelandic Sheepdog have double dewclaws, including two on each of their hind legs. In the Great Pyrenees, these may function as a sort of brake, since the dogs often race down mountainsides chasing wolves away from flocks of livestock.

The Briard and the Beauceron are known for their dual guarding and herding purposes. The double dewclaws help them chase sheep-stealing predators over rough terrain.

Should dewclaws be removed?

There is some debate as to whether dewclaws should be surgically removed. The argument for removal states that dewclaws are a weak digit, barely attached to the leg. They can rip partway off or easily catch on something and break. This can be painful and make the dogs prone to infection. The removal of the dewclaw results in a smoother, cleaner, straighter appearance of the leg in short-coated breeds.

Dewclaw removal is most easily performed when the puppies are newborns, around two to five days of age. It can also be performed on older dogs if necessary, although the surgery will be more difficult at that time. When the surgery is done on an older dog, it can be challenging to prevent the dog from licking at the incisions while they heal. Bandages, Elizabethan collars, basket muzzles or bitterant ointments may be used to stop the licking and prevent infection.

Broken dewclaws are painful injuries that may require working dogs to be out of commission while they heal. The quick of the nail contains nerve endings and blood vessels. Dogs with broken dewclaws will be limping, bleeding, swelling or obsessively licking at their feet.

Those opposed to dewclaw removal cite anatomical studies that show there are several tendons that connect the muscles of the lower limb to the dewclaw. These muscles indicate that dewclaws have a function as the dog moves. During running, the dewclaw digs into the ground, preventing twisting or torque on the rest of the leg.

Some veterinarians report a higher incidence of foot and carpal (wrist) injuries, arthritis and tendonitis in dogs whose dewclaws have been removed. So, while the removal of the dewclaw may prevent a break, it could create significant issues later in life. In the case of a traumatic injury to the dewclaw, it can be removed at that time.

Since dewclaws do not get worn down as readily as other toenails and may be hidden under heavy coats, it is important to keep them trimmed. This should prevent them catching on things and breaking. Occasionally, dewclaws will grow around in a circle and penetrate into the skin, so regular maintenance is important.

Why are my dog’s toenails breaking off?

There is an interesting nail disease that dogs get called symmetric lupoid onychodystrophy (SLO). It causes the nails to become brittle, split and crack. The nail problem originates in the claw bed, and the cause is not yet known. SLO can be a disease process on its own or a symptom of another disease, such as leishmaniasis. There may be a link between SLO and thyroid disease. Food allergies have also been thought to be a possible factor.

While SLO occurs in all breeds, large breeds are more commonly affected. It usually starts around the age of two to six years. This can be a painful condition. These dogs are reluctant to have their feet examined. The toes may be swollen, causing the dog to be lame.

Typically, the first sign is licking of the nails. The claw separates, elevates from the nail bed and falls off. In a short period of time, all the toenails on all four paws are affected to varying degrees. The claws will regrow, but they will be misshapen, dry, brittle and crumbly. There may be bleeding beneath a retained nail. Secondary bacterial infections occur with pus forming under the nail.

How is SLO diagnosed?

The first diagnostic test performed by the veterinarian is a slide of cells from the nail bed to look for infection. If bacteria or yeast are present, these infections are treated first. Bacterial and fungal cultures are recommended to identify the organisms present and determine to which medications they are sensitive. Extremely swollen toes should be X-rayed to rule out tumors or osteomyelitis.

If symptoms persist, a biopsy is performed to confirm the diagnosis of SLO. In order to get the most conclusive biopsy, the end of the digit should be submitted. The dewclaw is the preferred site for this. Sloughed claws do not usually contain the claw bed, which is the tissue needed for diagnosis. A newly sloughed claw can be used for the bacterial and fungal cultures.

Is there treatment for SLO?

Treatment for SLO is very safe, but may take several months for a response to therapy due to the fact that dogs toenails grow slowly. In some cases, treatment can be needed for the life of the dog. When treatment is discontinued, the SLO may recur.

Antibiotics, such as tetracycline or doxycycline, with niacinamide is one treatment option. Omega-3 and omega-6 fatty acids are necessary for healthy skin and toenail growth. Biotin may be given orally with meals to strengthen nails.

Pentoxifylline is a drug that decreases inflammation and dilates blood vessels. It treats poor blood circulation by improving the flow of blood through the vessels. It has been prescribed for dogs with SLO with mixed results.

More aggressive treatments with steroids, immunosuppressive drugs or “declawing surgery” are rarely prescribed. Antiseptic foot soaks and careful nail trimming are recommended.