What Are Those Black Spots on My Dog’s Skin?

What Are Those Black Spots on My Dog’s Skin?

Many dogs develop black spots or dark patches on their skin. While some of these blemishes are harmless, others signal the presence of a more serious problem.

Skin problems are common in dogs, and include everything from allergies to yeast infections. But what does it mean when your dog develops flat black spots or stains on his skin? This is also a common issue, and can have a variety of causes ranging from benign to serious. Read on to find out what these black patches might mean, and what you can do about them.


As always, a good first step is to take your dog to the vet, especially if the black spots appeared recently, look irritated, and/or are bothering him.

DID YOU KNOW? Skin discoloration, including dark patches, can occur in the case of fungal or bacterial skin infections.

A yeast infection in its early stages may have a slight smell, and show minimal hair loss or skin crusting as well as discoloration. In severe cases, the smell will be foul and dog might lick and scratch at the area, or even cry out from the discomfort.

According to veterinarian Dr. Joycelyn Quan, a skin cytology test is a simple and cost-efficient way to diagnose a dog’s skin changes at the surface level. During a cytology test, the vet will press a tape strip firmly against your dog’s skin while rubbing back and forth to take a sample of the affected area.

One of the great advantages of testing skin this way is that it’s painless and non-invasive. If the veterinary clinic has an in-house lab, the vet can look at the sample under a microscope and be able to tell you right away whether the problem is being caused by overgrown yeast, or a different type of fungus or bacteria on your dog’s skin.

HEALTH TIP: Make sure to dry your dog properly after a bath, particularly in areas that fold or crease, such as the ears, armpits, or any hanging/extra skin around the face or body.

If the cytology report shows a different type of fungus, for example, your vet will determine whether it’s a localized infection only present on the skin (fungal dermatitis), or order more extensive testing to rule out systemic fungal infections that can affect your dog’s organs or internal systems.

Whatever it reveals, a cytology report is a great tool for diagnosing skin problems and deciding on the best course of action.


Depending on the severity of the infection, it may require topical treatment with a medicated shampoo, ointment, cream, or wipes, as prescribed by your vet. Dr. Quan advises that if you need to use medicated shampoo, end the bath with a final coat of shampoo containing natural moisturizers such as coconut, oatmeal or vitamin E before rinsing her off. This final step is important because medicated shampoo is very drying; a hydrating shampoo helps remoisturize the skin at the end of the medicinal bath.

An overgrowth of yeast or a bacterial infection may also be treated internally with antibiotics.

In the case of a yeast infection, your vet may suggest a cone for your dog, since continuous licking of the affected area only worsens the condition. This is because yeast requires moisture to grow, so more licking means more yeast, which leads to darker, thicker, hardened skin. Preventing any licking is essential as the skin heals.

Several natural at-home remedies are effective at combating early stage yeast or microbial infections. Coconut oil, apple cider vinegar, and kefir help kill yeast and certain bacteria, and can be added to your dog’s diet and/or applied topically to the affected area. Diluted oregano oil may also be applied to the spots. Never put any liquids in your dog’s eyes or ears unless your vet instructs you to do so via drop administration.

If you have to give your dog antibiotics, Dr. Quan strongly recommends also giving her probiotics, since antibiotics are known to destroy both good and bad bacteria. Honey, plain chicken or turkey broth, as well as plain yogurt or goat’s milk are also helpful for maintaining balance in your dog’s gut during antibiotic use.


While certain breeds are predisposed to skin conditions, dark or black spots can also indicate your dog’s immune system is not functioning at its best because of allergies. Black spots can be caused by allergies incited by seasonal changes or environmental factors such as pollen, dust, grass, or excessive heat/moisture.

DID YOU KNOW? Black stains on the skin can also result from allergies caused by flea, mosquito or tick bites, as well as food allergens like grain, corn or soy.


Again, it’s important to see the vet to get to the root of what’s causing your dog’s allergies – whether it’s insect bites, pollen, or some type of food.

  • In many cases, changes to your dog’s diet (including treats), as well as his grooming and hygiene routine, may be all that’s needed to help calm his skin.
  • Supplements such as Omega-3 fatty acids, brewer’s yeast, bee propolis or colostrum are great immune boosters during allergy season and can help improve your dog’s skin health.
  • Naturally repelling fleas, ticks and mosquitoes helps prevent insect bite allergies and the darkening skin that can go with it. Wipes containing quality essential oils that bugs hate can be applied to your dog’s coat before you take him out.

DID YOU KNOW? Wipes made with aloe, oatmeal, or lavender are also great for soothing irritated areas.


Another cause of darkened skin is hyperpigmentation. There are two types:

  1. Primary hyperpigmentation is often seen in younger dogs and is due to genetic factors.
  2. Secondary hyperpigmentation manifests as an effect of an underlying problem such as allergies and skin infections (as discussed above), but can also occur due to dermatitis, hormonal imbalances, and immune systems deficiencies.


Though not likely curable, primary hyperpigmentation can often be managed with medication if inflammation is present. If the darkened skin areas are solely of cosmetic concern, medication may not be necessary. Secondary hyperpigmentation, meanwhile, is often curable and disappears once the root cause is identified and properly treated.


Occasionally, black stains and darkened skin patches can be caused by more serious health problems such as Cushing’s disease or lupus. However, the presence of these diseases is usually accompanied by other symptoms such as increased urination, a swollen belly/enlarged organs, lethargy, or excessive panting. Black spots can also be a sign of a type of skin cancer called malignant melanoma, especially if the area is irritated and doesn’t heal.

Due to the wide range of conditions that can cause dark spots or black stains on your dog’s skin, a visit to the vet is essential. By having your pup properly diagnosed and treated, he can say goodbye to any additional symptoms such as itchy skin, pain, discomfort or hair loss, and go back to living his best life, with healthy skin to match.

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