Why does my dog get Black Spots and some can be Itchy with Hair Loss and Crusty Skin?
What Are Black Spots on Dogs Skin?
Black spots usually appear on the abdomen, tail, or the back of your dog, black spots on the fur and skin of your pooch are usually an indication of hyper-pigmentation. Hyper-pigmentation results from an increase in natural pigments called melanin.
Maltese have higher tendency to show signs of hyper-pigmentation than others because of their characteristic white coats. Hairless dogs also have a higher tendency because of their hairlessness. Hyper-pigmentation commonly affects the skin and fur but it can as well occur on the nails of your canine.
The black spots are in most cases harmless, especially if they are not accompanied by signs of irritation and only affect the fur with no changes to the underlying skin.
You should be concerned if the skin seems irritated or other symptoms appear including:
Hair loss
Severe itching/scratching
Bleeding
Crusty
Fluid-filled bumps
Lumps that extend beyond the surface of the skin
Thickened and crusty/scaly skin
What Causes The Black Spots?
Exposure to the sun is the most common cause of black spots in dogs skin and fur. Ageing is also known to cause dark spots in canines (age spots). Friction can also cause dark patches in areas such as armpits and under the legs. Watch for these spots especially if you put clothing on your dogs. I put clothes on my Chinese Cresteds in the winter and have gotten these black spots on their skin. Other than these rather normal causes, various skin conditions such as Acanthosis nigrans may as well be the underlying cause for black patches on the skin.
Skin Conditions that Cause Black Spots:
Cushing’s disease
Cushing’s syndrome, known as hyperadrenocorticism. Cushing’s disease is a condition whereby the adrenal glands go into overdrive in producing certain hormones. It is commonly caused by a tumor in the pituitary gland (which accounts for 85-90 percent of all cases), tumor in the adrenal gland, or overuse of certain medications, especially steroids.
In addition to increased appetite, thirst, and increased urination, Cushing’s syndrome also causes lethargy in the dogs and unhealthy-looking fur. It also typically causes distended abdomen (pot-bellied appearance) and dark spots on the skin among other symptoms.
The appropriate treatment for Cushing’s disease varies depending on the underlying cause. Is it attributed to pituitary gland, adrenal gland or use of certain medications? Your vet will determine whether to use medications such as trilostane, mitotane, and selegiline hydrochloride, or to perform surgery to the affected gland. Discontinuation of the offending steroid may also be necessary.
Hypothyroidism
Hypothyroidism can also cause black spots in dogs skin. This is a metabolic disorder in which the thyroid glands become underactive and thus doesn’t secrete adequate amounts of thyroid hormone. As a result, your dog's metabolism proceeds at slower than normal pace.
Although hypothyroidism affects all dog breeds, some breeds have higher propensity to it than others, in particular golden retrievers, Irish settlers, Doberman, boxers, cock spaniels, and dachshunds. Neutered male and spayed female dogs have also been shown to have higher risk of hypothyroidism.
Hypothyroidism first shows as hair loss on the trunk, back of the hind legs, and tail after which the coat turns dull and the skin gets flaky. Notable is the fact that the skin doesn’t get itchy. Black patches may develop before the onset of other symptoms such as weight gain, slow heart rate, muscle loss, lethargy, and persistent infections of the ear and toenails. Some dogs may even become infertile as the condition progresses.
Treatment of canine hypothyroidism involves daily intake of thyroid supplements. Levothyroxine or L-thyroxine is the medication used but the appropriate dosage is specific to each affected dog.
Hemorrhage (vasculitis)
Black spots on the skin could as well be the result of hemorrhage (bleeding) under the skin. This typically happens when your dog sustains bruises. This refers to skin injuries that cause the underlying blood capillaries to rupture and release blood into the surrounding tissues. This then leads to the characteristic dark colored skin discoloration.
The discoloration is usually attributed to presence of red blood cells. Most bruises clear away on their own given time. If they don’t go away in a couple weeks or so, however, it is advisable you take your canine to the vet to rule out vasculitis.
Allergies
Allergies can as well cause dark spots on the skin in addition to other symptoms such as itching and paw licking. Check out my articles on Allergies.
Black Spots on Dogs Skin Looks like Dirt
Black spots on your pooch’s skin that looks somewhat like dirt is usually an indication of yeast infection especially if they show around the groin area. Such spots are usually flat or flush with the skin and tend to appear in the groin area first (around the genitals) before showing up in elsewhere on the skin.
Yeast infection is usually caused by an overgrowth of Malassezia pachydermatis. This is an opportunistic but normally harmless fungus that is commonly found in areas such as the ear canal, anal sacs, inter-digital area (the space between a dog’s toes), vagina, and rectum.
Yeast infection occurs when this yeast takes advantage of the prevailing conditions to erupt in an overgrowth. Usually this happens when an underlying condition e.g. allergies, bacterial infections, etc. weakens the immune system. Prolonged use of some medications e.g. antibiotics, prednisone etc. can also trigger a yeast infection.
Yeast infection is usually associated with intense itching alongside other symptoms that vary depending on the nature of the infection. When it is generalized, that is involving most areas of the skin, yeast infection causes an offensive smell and the pooch’s skin often appears oily and scaly or crusty. Localized cases of yeast infection usually involves the ears, anal area, toes, or muzzle and may be manifested in constant scratching of the affected area and paw licking alongside other symptoms such as hair loss, black spots (hyper-pigmentation), and crusty skin.
Treatment of yeast infection starts with identifying the underlying condition responsible for immune-suppression like allergies for example. Once identified the condition should be treated along with the Malassezia yeast. I suggest using the "Famous Yeast B Gone" with the "Famous Healing Salve" or the "Famous Yeast B Gone Kit" to treat the skin. I also have an oral Suppliment called "Famous Allergen support".
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