Pet parents spend a lot of time worrying about their fur babies. One thing some dog owners worry about are black toenails. Assuming that your dog isn’t going through a Goth phase, you may be wondering why their nail turned black. Is it normal, or is it a potential health issue?

Why has my dog got one black nail?

Maybe you have a new puppy and discovered that one of their nails is black. Perhaps you’ve had your dog for a while and have always been curious about their black nail. Perhaps you were inspecting your dog’s nails, and realized that one nail has changed color. 

A change in nail color can be benign, or indicate a health issue. 

Natural Pigmentation

Your dog may have a black nail due to natural pigmentation. They may have always had one black nail. It’s also possible that their pigmentation is changing, causing the nail to change color. 

Generally, dogs’ pigmentation gets lighter as they age, just like humans. However, it is possible for a nail to turn black as your dog ages and pigments change. 

Trauma

Trauma is the most common cause of one nail turning black. Most disorders that cause nails to change color will affect more than one nail. If trauma only occurs to one nail, it will only affect that nail. 

Trauma can occur from many everyday situations. Jumping onto a hard surface or playing with another dog can cause minor injury to the nail. Something falling on the toe can also cause the nail to turn black. 

If the injury is minor, you can allow the nail to heal on its own. If your dog seems to be in pain, a vet visit is a good idea. 

Trauma can cause the nail to turn red or black. It’s essentially the same as a bruise, which causes blood to pool under the skin or nail. 

Detached Nail

A detached nail can also cause the nail to turn black. This occurs when the nail is partially detached, but hasn’t completely fallen off. This occurs as a natural process, but it can also occur due to trauma. 

If you don’t see bleeding or signs of pain like limping, the nail is likely to fall off naturally. If you see signs of bleeding or pain, the nail may have gotten caught on something. 

If your dog has long nails, this is more common. Long nails can get caught on a bed, blanket, or even the ground. When your dog moves its foot, it pulls the nail, removing it from the nail bed.  

Infection

Your dog’s nails can get infected. Fungal, bacterial, and yeast infections are common causes of black nails. Fungal infections can cause your dog’s nails to turn white, brown, or black. Yeast infections typically turn the nail brown or red. 

If it’s caught early, the infection may only affect one or two nails. If it’s allowed to progress, it can affect one or more paws. 

Other symptoms of an infection include limping, swelling at the base of the nail, itching or pain, and excessive licking. 

Why are my dog’s nails turning black?

If your dog has more than one nail turning black, there are many potential causes. 

Allergies

Allergies can cause your dog’s nails to turn red or brown. This usually occurs because the dog is allergic to something they come into contact with in their environment, like grass or dust. 

Allergies can also cause excessive licking, and make your dog more susceptible to nail infections. 

Age

Just like humans, dogs hair can change color as they age. Their nails can change color as well. It’s more common for nails to become lighter with age, but it’s also possible for them to turn darker or black. 

Auto-Immune Disorders

Auto-immune disorders are thankfully rare in dogs. The most common autoimmune condition that causes nail discoloration is symmetric lupoid onychodystrophy, or SLO. 

It’s more common in certain breeds, including shepherds, spaniels, and schnauzers. It occurs in young to middle-aged dogs. Signs include splitting of the nail, the nail falling off, and discoloration. 

The cause of the disorder isn’t known, but it’s suspected to be a genetic disorder. 

Excessive Licking

Excessive licking can occur for several reasons. Allergies, trauma or injury, and infection can all cause your dog to lick their paw excessively.

It’s essentially their way of attempting to relieve pain and discomfort. If you smash your finger, you may put it in your mouth. If you bruise your shin, you’ll rub it with your hand. Dogs use licking in the same way. 

The other cause of excessive licking is OCD. Dogs who experience anxiety often lick as a self-comfort mechanism. The behavior can become compulsive, leading to OCD. 

Licking can cause your dog’s nails to become black or discolored. This is particularly common if your dog’s saliva is overly acidic. 

Nutrition

Nutritional deficiencies can also cause black nails. This is unlikely if your pet is eating a balanced diet and doesn’t have autoimmune or digestive issues. 

Hypothyroidism

Hypothyroidism occurs when the thyroid is underactive. The thyroid controls metabolism. When metabolism slows, it can cause many health issues. Lethargy, skin problems, hair loss, and weight gain are common symptoms. Dogs with hypothyroidism are prone to nail infections, which can cause the nail to turn black.

Are black nails normal for dogs?

Yes. Depending on the breed and color of your dog, black nails can be perfectly normal. It is important to distinguish normal black nails from black nails indicating a health problem.

Black nails are common for dogs who have black, brown, or multi-color coats. Your dog’s nails can also have stripes, or differently colored nails. Some dogs have white nails and black nails. 

Signs of Nail Problems

Since it’s possible for your dog’s nails to be naturally black, it’s important to know the signs your dog has nail problems. Nail problems can be more difficult to identify in dogs with black nails, because discoloration is often the first clue dog owners notice. 

One of the most telling signs of dog nail problems is lameness or limping. If a nail or paw is causing pain, your dog will naturally lessen the weight on the foot. 

Problem nails are often misshapen or brittle. If you notice your dog’s nails look different than normal, this may mean they have a nail problem. Nails can also be fragile and break easily. 

Swelling around the nail bed and pus around the nail can occur with a nail infection. Lastly, your dog may lick their paw frequently if they are experiencing nail problems. 

What to do about my dog’s nails turning black?

What to do will vary based on the reason your dog’s nails are black. If your dog is showing any signs of nail problems, a vet visit is needed. Your vet can assess your dog’s nails and determine if there’s a problem, or if it is just their natural nail color. 

Treatment

Infections are the most common causes of your dog’s nails turning black due to a health issue. Topical and oral antifungals or antibiotics are used to treat these infections. They are much easier to treat when they are caught in the early stages. 

If trauma is the cause, your vet may remove the nail, or simply monitor its condition. In some cases, the area may need to be bandaged. 

If your dog is excessively licking the paw, you may need to use a cone to prevent the licking. 

Keep the nails and feet clean. This will help it heal without infection. 

Prevention

The best way to handle black nails due to nail problems is to prevent them in the first place. Regular nail trimming is important if your dog has long nails. 

If your dog is active, they may keep their nails short through regular activity. Dogs in the wild never get their nails trimmed. Instead, they wear a bit at a time during their regular activities. 

You may find that your dog’s front nails require clipping, but the back nails don’t. This is because the back legs are used differently than the front legs. 

While clipping your dog’s nails is important, you shouldn’t clip them too short. This can also cause nail problems. If you are unsure, err on the side of caution and leave them a bit long. You can also entrust your dog’s nails to a groomer. 

Lastly, you should inspect your dog’s nails biweekly. Look for any changes in the nail shape, thickness, and color changes. Check for swelling and tenderness around the nail. If your dog’s nails look normal, chances are you have nothing to worry about. 

If you notice any changes or soreness, check with your vet. The earlier nail problems are treated, the easier the treatment is for your pooch. 

Author

I created and currently manage Pet Dog Owner, the website you can go to when you have questions about your dog's behavior. It is my hope that you find Pet Dog Owner to be a helpful resource. It is also my hope that it will help you to improve your relationship with your dog. You can read more about me and my website here.