White dogs are often prone to browning discoloration due to a variety of factors. Some are cosmetic, others are dietary, and some are related to health; but nearly all can be successfully addressed with time and attention. Some dogs’ fur darkens with age, which could be a normal occurrence for your pup. If the discoloration is sudden, or if your dog exhibits any unusual accompanying physical symptoms, like listlessness, decreased appetite or weight loss, consult your vet immediately.
Excessive tearing can create the appearance of brown stains around a white dog’s eyes. Sometimes blocked tear ducts are the cause, sometime’s a dog’s shallow eye sockets are to blame. This condition is especially prevalent in short-nosed dog breeds. You can reduce the brown discoloration by regularly wiping your dog’s eyes to remove discharge, applying a commercial anti-tear stain agent, or grooming. An effective way to reduce the brown hair around your dog’s eyes is to ask your groomer to trim the area around the eyes short. Let a professional handle this delicate work, as doing it yourself can be tricky and dangerous.
If your dog eats food or treats, or gnaws on chew toys, that have brown or red pigmentation, it has the potential to stain white fur brown. This can be especially prevalent with wet foods, which have the potential to cause immediate staining. Look for foods without coloration or dyes. Oxidation of saliva can also turn white fur brown where a dog licks himself. Wipe your dog's face after a messy meal, but don’t use products that contain bleach, as they can irritate you dog’s skin.
Injury or Allergy
If your dog has an injury, allergy or skin irritation, the white fur surrounding it could potentially turn reddish-brown. This may be from excessive licking or scratching, or dried blood. Have any browns fur patches that appear suddenly inspected to ensure your dog hasn't been bitten or developed a rash. Consult your vet for advice if this is the case.
If your white dog is frequently outside, browning fur may be the result of playing in dirt piles or rolling in rubbish. High mineral content in water is another cause of discoloration. Regular brushing and bathing can resolve this situation. You can purchase special commercial shampoos designed specifically for white dogs.