It's nice to sit with your dog, and give him a rub on the belly, but when you see blotches and spots on his tummy skin, it can give you a fright. You probably have no idea what they are, and you may not know how long they've been there.
In many cases, these blotches are quite normal, and may be present from birth. Some dogs develop dark patches on their skin as they get older. They aren't itchy or scaly, the skin isn't thickened and they don't cause the dog any harm at all. There's no need to worry about these, unless your dog is losing hair in these patches. This usually indicates there's a problem, such as an infection, that needs attention.
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By far the most common cause of darkening of a dog's skin is irritation and trauma from licking or scratching. If the blotches have appeared suddenly, it may be an allergic reaction. Dogs can react to plants or insect bites, which may cause multiple blotches and welts to develop on the tummy skin. They may then scratch at the welts, which can make their skin worse. You'll find that an anti itch spray will help stop the itch and soothe the inflammation, and help to return the skin to normal.
Dogs can also develop a bacterial infection on their tummy, either with or without an allergy. The blotches from a bacterial infection tend to be round, and they often have a crust around the edge. They're very itchy, and again, the scratching may lead to dark patches on the tummy skin. These dogs usually need antibiotics from their vet to get the infection under control and stop the itching.
You do need to treat inflamed skin very gently. Look for a shampoo that contains colloidal oatmeal, and herbal extracts which will relieve the itch, and make your dog more comfortable.
Some Blotches Are Slower To Show
Older dogs with an underactive thyroid gland may develop patchy discoloration on their skin. They often have lower than normal energy levels, and sleep a bit more than usual. It's simple to diagnose this disease - your vet will take blood to check your dog's thyroid hormone levels and if they're low, he'll prescribe thyroid hormone tablets for him.Some blotches take a bit longer to develop. A dog's skin can freckle when it is exposed to too much sunlight. These blotches may be associated with sun damage, particularly if your dog is white, or has pale tummy skin. If you don't take steps to protect him with sunscreen, these blotches can progress to sun cancer. Symptoms of sun cancer in dogs can look very much like a bacterial infection - red blotchy marks on the skin, flakiness and itching. A biopsy will confirm that cancer is present, and your vet can surgically remove the cancerous spot. Good options are sunscreen made specifically for dogs, or putting a t-shirt on your dog to protect the area from further damage.
Auto immune diseases occur when the immune system attacks the body, and they may take several forms. In one case, the immune system destroys the platelets in the blood, so it can no longer clot. You'll see reddish purple blotches on the tummy skin where there has been bleeding from the capillaries. This is a very serious illness indeed, and you need to see your vet as soon as you can.
In most dogs, spots on the tummy aren't a big problem at all. However, they can be itchy and annoying, so it's important that you use the correct products to keep your dog as comfortable as possible.