Beneath their furry coats, dogs and cats come in a variety of hues. Some have pink skin. Others are gray, freckled, or black. As long as the color stays constant from year to year, there isn't a problem. Changes in skin color, on the other hand, mean that something is going on.
A yeast infection, for example, will cause the skin to get darker in places. Vets call this condition hyperpigmentation, says Richard K. Anderson, D.V.M., a veterinary dermatologist at Angell Memorial Animal Hospital in Boston. The yeast organism is most comfortable in warm, moist places, so you are most likely to see these dark patches on the neck, armpits, or groin. Pets with yeast infections often have a slightly rancid odor, and they may be itchy as well.
Changes in skin color can also be caused by simple friction. When pets lick or scratch the same area for a long time because of allergies, for example, pigment-producing cells in the skin get overactive making the area look darker.
Dark patches aren't always harmless, adds Thomas P. Lewis II, D.V.M., a veterinary dermatologist in private practice in Mesa, Arizona. They may be caused by a type of skin cancer called melanoma, which typically occurs on the feet or around the mouth. Other skin cancers may cause white or red crusty areas. "These often occur on the face, ear tips, or other areas that get a lot of sun," he says.
A number of the body's hormones, including those produced by the thyroid and pituitary glands, play a role in regulating melanin, the skin's natural pigment. Pets with a hormonal imbalance may produce too much melanin, causing the skin to get darker in places or even all over.
Dogs and cats that have spent too much time in the sun will occasionally get a little pink on their faces, the tips of their ears, or on their soft, hairless bellies. In addition, pets with lupus or other immune system problems will sometimes get a slight rash after even brief exposure to sunlight, says James Jeffers, V.M.D., a veterinary dermatologist in private practice in Gaithersburg, Maryland.
In pets as in people, jaundice -- a condition caused by liver disease or sometimes internal bleeding -- can turn the skin an unhealthy-looking yellow, says Vance Case, D.V.M., a veterinarian in private practice in Sunbury, Pennsylvania. At first, pets with jaundice will show a little yellow in the ears, on the gums, or in the whites the eyes. Over time, the color changes will appear elsewhere on the body and may darken to more of a pumpkin color. Jaundice is serious and always needs to be treated by a vet, says Dr. Case.
See Your Vet If...
- Your pet is licking or scratching the same spot
- She has a slightly rancid odor
- Your pet spends a lot of time in the sun
- Her skin is slightly yellow
- Your pet is shedding or scratching more than usual
- He has scales, bald patches, or a rash
- He has severe dandruff or dry skin
- His fur is greasy or smelly even after baths
- Your pet has broken out in hives and is having trouble breathing
- He has a bad sunburn
- There has been a significant change in skin color, or the skin seems loose
- There is a lump or swelling beneath his skin
- Your pet has a sore on the skin that won't heal
- The skin of the lips, abdomen, or rectal area is yellow
- There are red or purple dots or splotches on his skin
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