Dogs can get dirty rather quickly, especially if they are light colored. Most of the time, coat discoloration results from something they've gotten into. Dirt, garbage and miscellaneous grime that dogs seem to find can all leave ugly, stubborn stains on a light coat, but those stains are easy to recognize. However, if your dog has pink stains on its paws, it could be a sign of a skin infection.
Cause of Discoloration
Owners of white or light-colored dogs may occasionally notice a sudden discoloration of their dog's fur, causing it to turn pink. This means that an enzyme found in the dog's mucous membranes is reacting with oxygen and staining the hair. When the stains are under the eyes, they are called tear stains, and are the result of watery eyes running into the hair. When the staining is found elsewhere on the body, it means the dog has been chewing on its skin, and its saliva has reacted with the hair and oxygen exposure to cause staining.
Causes of Irritation
Anything that itches can trigger a chewing episode. When the feet are the body part in question, the most common cause is a mild skin infection caused by moisture between the toes, especially in dogs that swim. Sometimes a burr or other foreign object can become entangled in the hair or between the pads of the foot and cause irritation, and even walking on hot asphalt can cause irritation for a day or two. The spaces between the toes and between the pads are also a favorite hiding place for fleas and ticks.
Carefully examine your dog's feet, separating the toes and the pads. Check for fleas, ticks, bits of glass, pebbles or anything that doesn't belong. Remove what you find carefully, and wash the paw thoroughly with soapy water. Since your dog has been chewing at the foot long enough to cause discoloration, the skin is most likely red and inflamed, and slight swelling may be present; a liberal application of antibiotic ointment is a good idea. If you don't see an obvious cause for the itching, a trip to the vet is in order.
At the Vet
The vet will likely test the dog for mites, and thoroughly clean the paw with a surgical scrub. The paw will be dried and packed with a drying powder to wick away all traces of moisture, and may be lightly bandaged for the rest of the day. If your dog begins to chew the bandage, the vet will send it home with an Elizabethan collar to keep it from reaching it. If the irritation is severe enough that the skin is abraded or broken, the vet will prescribe a short course of antibiotics to head off any infection that may occur.
The prognosis for skin problems is generally good, especially for acute cases brought on by a foreign object. If parasites are the culprit, adhering to a thorough treatment plan will eliminate them quickly. If a chronic skin infection or allergy is to blame, changes in diet and lifestyle can bring the condition under control and reduce the occurrence of flare-ups. Unfortunately, the discolored fur will not go away--the only way to get rid of it is to cut it off. To prevent future problems, always dry your dogs feet thoroughly after exposure to moisture. A monthly dose of flea and tick preventative will keep parasites away, and a regular paw-check will allow you to discover foreign objects before they become a problem.