The essentials
- Hyperpigmentation isn’t a disease — It’s actually a secondary symptom in dogs, often caused by trauma to the skin.
- It happens over time — Skin discoloration is usually the result of chronic damage to the affected part of the body.
- Hyperpigmentation is usually harmless — As long as your dog isn’t experiencing any pain or discomfort, there’s likely no cause for concern.
When part of a dog’s body looks darker than the rest, it may be caused by an abnormal increase in the skin’s melanin production. This is known as acanthosis nigricans, or hyperpigmentation, and it usually appears as thick, velvety brown, and black areas of hairless skin. While some cases are thought to be breed-specific, most cases are usually symptoms of other skin conditions or metabolic problems, like allergies, infections, and endocrine (gland-related) disorders.
By itself, a change in skin color usually isn’t a cause for concern. But it’s important to address the root of the matter to keep your dog happy and healthy.
What causes hyperpigmentation in dogs?
Primary hyperpigmentation is a breed-specific condition that only affects dachshunds. In other breeds, secondary hyperpigmentation can be triggered by inflammation or friction related to several causes.
- Aging. Mild cases of hyperpigmentation can be normal as a dog ages. Their skin can get darker from exposure to the sun, especially if they have light or white coats.
- Obesity. Breeds that are prone to obesity are also more likely to develop secondary hyperpigmentation on their groin and back legs. These include Fox Red Labrador Retrievers, pugs, dachshunds, American Bulldogs, Cairn Terriers, Beagles, Cocker Spaniels, and Rottweilers.
- Hormone imbalances. When a dog has Cushing’s disease, their adrenal glands overproduce certain hormones like cortisol. This can trigger skin-related symptoms including dandruff, canine acne, and hyperpigmentation. Other endocrine conditions like hypothyroidism have similar effects on a dog’s skin.
- Allergies. The most common cause of secondary hyperpigmentation is chronic itching caused by conditions like contact dermatitis, which occurs when a dog comes into contact with a substance that irritates their skin. When a dog is constantly scratching, rubbing, licking, or biting their sore spots, it causes trauma that can lead to post-inflammatory discoloration over time.
- Skin infections. If you see any inflamed skin that’s red around the edges, there’s a good chance it’s infected. Bacterial and yeast infections are the most common skin infections in dogs, and they can come on suddenly or become chronic if they keep recurring. Other conditions like mange and ringworm cause itchiness that leads to scratching and discoloration, though this type of hyperpigmentation tends to fade as the underlying infection is treated.
- Tumors. Mast cell tumors often appear on a dog’s skin as red, ulcerated, or swollen bumps. However, they do not commonly cause hyperpigmentation. In some cases, pigment discoloration is localized to where the tumor is located.
🚨 Take your dog to the veterinarian immediately if you spot any suspicious skin growth.
How to spot hyperpigmentation in dogs
Hyperpigmentation initially appears as a darkening on a dog’s belly, leg, armpit, and groin areas, which tend to receive the most friction. Over time, these areas become inflamed, triggering irritation that causes the dog to scratch themselves and further irritate the skin. This leads to changes like thickened skin, hair loss, odor, and pain. If left untreated, these areas are likely to become infected, worsening the irritation and, subsequently, the other symptoms. In the case of primary hyperpigmentation, symptoms usually appear within the first year of a dog’s life.
Skin conditions often seen with hyperpigmentation
Since hyperpigmentation is a symptom of an underlying condition, it’s not uncommon to see it accompanied by other adverse reactions. These include:
- Alopecia. Alopecia is the partial or complete lack of hair in areas where it is normally present. Hair loss like this commonly affects the parts of a dog’s body affected by hyperpigmentation.
- Lichenification. Yeast infections like Malassezia dermatitis have been known to trigger this reaction in dogs, which causes lesions that are thick, exaggerated, and have a pebble-like appearance.
- “Café au lait” spots. These birthmarks are areas of increased melanin production, but much like human freckles and moles, they’re usually quite harmless. Since café au lait spots aren’t caused by an underlying condition, they can’t be cured.
Treating hyperpigmented dogs
There’s no cure for inherited hyperpigmentation. But, you can manage it with soothing topicals like anti-seborrheic shampoo, vitamin E oil, melatonin, and steroid ointments. Early cases of secondary hyperpigmentation will also benefit from these treatments. If your dog’s hyperpigmentation is only cosmetic, treatment might not even be required. However, if your dog’s black spots have become infected, you’ll need to see a vet. They can prescribe you the appropriate antibiotic or antifungal medication. The vet may also recommend topical treatments like medicated shampoo to help soothe your dog’s skin.
No matter what kind of hyperpigmentation your dog is experiencing, it’s always best to get them seen by a veterinarian. A vet will be able to run the appropriate tests and determine the best treatment for your dog. Stay consistent with it, and there’s a good chance your dog’s skin will eventually return to normal over the next few months. In some cases, the pigment never fully returns to normal, but that’s OK, as long as the affected areas aren’t hurting your dog. Trust the treatment and have patience.
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Frequently asked questions
What causes hyperpigmentation in a dog?
The most common type of hyperpigmentation in dogs is called secondary hyperpigmentation. It’s caused by inflammation or friction to the skin resulting from injury, infection, or a hormonal imbalance. Primary hyperpigmentation is a rare breed-based form that only affects Dachshunds.
How do you treat hyperpigmentation in dogs?
Treatment differs depending on the underlying cause of the hyperpigmentation. Primary hyperpigmentation is inherited and has no cure. Infections contributing to secondary hyperpigmentation are often treated with antibiotic or antifungal medication. Medicated shampoos and steroids can also provide itch relief.
How long does it take for hyperpigmentation to fade in dogs?
When you start treating your dog’s hyperpigmentation, it can take weeks or months for their skin to heal and regain its normal appearance. In some cases, the skin may never go back to its original pigment.
What home remedy is good for hyperpigmentation in dogs?
If your dog’s skin is bothering them at home, consider giving them a 15-minute oatmeal bath for some natural itch relief. Certain foods like fat-free yogurt are also said to boost dogs’ skin disease resistance. But refrain from feeding them anything new until you ask a vet about it.
