Black Scabs on Dog: Top Reasons & What to Do

This article was updated on September 23rd, 2023

No owner wants to find black scabs on their dog. Not only are they unsightly and feel unpleasant, but they could also indicate something more sinister going on. Black scabs on dogs come in a range of different shapes and sizes. As a vet, I see black scabs of one form or another most days in the clinic. 

The majority of black scabs will be insignificant, posing no threat to your dog. However, some black scabs could be linked to a more serious underlying cause. As an owner, it’s important to know the difference.

What does it mean if a scab is black?

Black scabs are similar to other scabs in that they are dry, crusty lesions that often develop following a wound or inflammatory process in your dog’s skin. However, the difference is that black scabs are also hyperpigmented—giving them a darker appearance.

While this darker appearance can just indicate that the scab is older, hyperpigmentation usually occurs when excess melanin accumulates in the skin, resulting in the darkening of the skin’s surface. This process can occur spontaneously or following inflammation of the affected area.

Types of black scabs on dog’s skin

Here is a list of the most common causes of black scabs in dogs:

1. Wounds

One of the most common reasons for a black scab forming on your dog’s skin is following a wound. When your dog gets a scrape or a cut, blood leaks from the area and forms a clot, composed of platelets and red blood cells. Clots are helpful in that they prevent further bleeding from occurring.

As time goes by and the wound heals, the clot dries out and forms a scab. This provides a protective layer over the vulnerable wound underneath while it heals. The scab will often darken as it gets older and the blood dries up, sometimes to the point where it appears black.

Most wounds will heal on their own if not aggravated. On the other hand, if your dog has a tendency to lick at wounds, then they might require an Elizabethan collar. Larger wounds may require stitches or staples, so be sure to seek veterinary advice if this is the case.

2. Allergies

Dogs can suffer from allergies in a similar way to humans. An allergic reaction to something in your dog’s environment or their food results in inflammation of their skin. This appears as redness, a rash, or hives on the surface of your dog’s skin and can be very irritating for them.

While an acute allergic reaction may cause redness of the skin, more chronic allergies can result in a darkening of the skin, sometimes to the point where the skin appears black. This is because, over a longer period of time, inflamed skin can become hyperpigmented. As this skin sheds, it can appear as black scabs. 

If your dog has been suffering from allergies for a prolonged period of time, then it may be best to get your veterinarian involved. Acute allergic reactions often require steroids or other anti-allergy medication. Food allergy trials or blood tests may also be needed to identify the underlying allergen.

3. Parasites (or itching excessively due to parasites)

Parasites, like fleas or mites, living on your dog’s skin can cause black scabs to appear. Fleas don’t spend long on your dog—they bite and jump off—but they do leave behind feces. Flea feces look like small bits of black dirt on your dog’s fur, and they can also look like black scabs. 

Mites also affect your dog’s skin by burying under the surface of the skin or affecting the hair follicles. This results in inflammation and extreme irritation. Dogs with a mite infestation will often frantically itch at themselves to the point of causing self-trauma. The wounds that your dog causes while doing this will form into scabs, which often become darker in color as time goes on. 

It’s very important to keep your dog’s anti-parasite medication up to date to prevent such parasites from taking up residence on your dog. If you think that your dog may have an active parasite infestation then seek veterinary advice. 

4. Growths

Some growths on your dog’s skin can appear like black scabs. Lumps, warts, and masses can grow anywhere on your dog’s body. Sometimes these will contain hyperpigmented tissue, giving them the appearance of a black scab.

It’s also possible that your dog is itching at a mass and causing trauma, which then forms into a black scab as it heals. 

While many skin growths are benign, not all of them are. A certain type of skin mass called melanoma, which contains a lot of the black pigment melanin, often appears very black by definition. These are malignant, or cancerous, lesions of the skin and should be investigated by your veterinarian immediately.

Moreover, any masses on your dog’s body that are growing rapidly, changing shape or texture, or that appear very black should be checked out by your vet. 

5. Hyperpigmentation

Another reason for what looks like black scabs on your dog’s skin is simply hyperpigmentation (Black spots on dog skin). Pigment is naturally found within your dog’s skin to differing degrees and in different parts of their body. Sometimes an area can become very dense in pigment, or hyperpigmented, and this can appear as black scabs. 

Hyperpigmentation has many causes. These include genetics, hormonal imbalances, allergies, and skin infections. For the most part, it isn’t too much of a worry, as long as your dog isn’t showing any other symptoms of being unwell. If you’re at all concerned, have your vet check it out. 

Can I just monitor my dog and wait if my dog has black scabs?

There may be some situations where it’s fine to just monitor and leave a black scab on your dog. This isn’t always the case, however, so it’s important to know the difference. 

Black scabs that have a known cause such as a recent wound or allergic reaction may be okay to monitor. Often these will resolve on their own. 

On the other hand, black scabs that have been present for a while or that are getting worse should be investigated. This is especially true if these scabs are associated with a lump or raised area, as this could indicate a malignant tumor. If you’re worried (for any reason) then it’s best to have your vet check over your dog.

3 steps you can take at home to help with black scabs

Scabs are the body’s natural way of healing, so the less interference, the better.

For dogs prone to licking or chewing at wounds, an Elizabethan collar such as this one can help to move the process along safely. There are also a few steps owners can take at home to ensure black scabs heal faster:

1. Gently bathe the scab with warm water. Don’t rub the scab too hard, as you don’t want it to peel off. Avoid any harsh chemical soaps since they can delay the healing process. 
2. Apply cream to the scabbed area. A vitamin E cream such as this will provide vital nutrients that allow the skin to heal. 
3. Once the cream has soaked in, apply vaseline to the area. This will provide a protective barrier over the affected area, preventing bacteria from getting in and keeping the area moisturized.

It’s important to remember that the above steps are no substitute for veterinary care. If your dog’s black scabs aren’t healing, see the vet immediately.

Time it takes for scabs to heal

The timeline for a scab to heal partly depends on the underlying cause. If this hasn’t been resolved, then scabs may keep forming. However, if healing in a healthy manner, most scabs will start to dry up and heal over the course of a few weeks. (Sometimes even quicker if the scab is very small.)

Signs that your dog should see a veterinarian

Scabs that keep recurring or that are becoming worse will require veterinary treatment. Black raised scabs or lumps should be investigated sooner rather than later for fear that they could be something sinister.

Similarly, if your dog is really bothered by the scab and keeps scratching at it then they will likely need treatment to help speed up the healing process. 

If your dog is displaying any other symptoms of being unwell such as vomiting, diarrhea, or general lethargy, then they should also be seen. 

How can a vet help with black scabs?

Vet diagnosis

In order to reach an accurate diagnosis, there are various tests that your vet might want to perform.

The first thing they’ll need is an accurate history of exactly what the issue is, when it started, and how long it’s been going on. Therefore, it’s important to have an idea in your head of the answers to these questions (see the next section). 

Your vet will also perform a clinical examination of your dog, focusing on the skin lesions in question. At this point, they might choose to take samples for testing or a trial treatment if the likely cause is obvious. 

Samples of your dog’s skin include skin scrapes, hair plucks, and impression smears—these are all examined under the microscope for clues as to what might be causing the black scabs. Your vet may also want to perform blood tests to look for signs of systemic illness. 

Questions your vet might ask you

Prior to visiting your veterinarian, it’s a good idea to have answers prepared to questions that they might ask you. This will not only save you time and money but will allow for faster diagnosis and treatment of the condition affecting your dog.

Questions your vet might ask include:

• When did you first notice black scabs on your dog?
• Are the black scabs getting worse or better?
• Is there any obvious cause of the black scabs such as a wound or injury?
• Is your dog scratching or bothering at the black scabs?
• Is your dog otherwise well in themself? Any other symptoms?
• Have you tried any remedies at home for your dog’s black scabs?

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