I found a big article about tear stains, it tells more about understanding, why dogs cry, why tears have red pigment. You can read it here: A Veterinary Guide to tear Stains
And here is what I understood in short.
First of all, where tears come from and why tears are red?
Some dogs produce excessive tears. But this can be managed quite easily if it is not health issue or because of breed specification (poodles, bichons, Maltese, boxers, bulldogs, etc..)
Please remember that young puppies will tend to produce more tears when they are teething. In puppy case just be patient and do as suggested below.
Its all because of iron-containing molecules. Tear stains are usually caused by dye molecules called porphyrins. Porphyrins are iron-containing molecules, produced when the body breaks down red blood cells. Porphyrins are excreted primarily through bile and the intestinal tract, but in dogs a significant amount of porphyrin is excreted through tears, saliva and also urine. When porphyrin containing tears or saliva sits on white fur for any length of time, stains result. These iron-related stains intensify/darken in the presence of sunlight.
All dogs produce porphyrin, but of course porphyrin staining is most noticeable on light colored dogs. If you have ever noticed a white dog who has been licking or chewing on his leg, the hair in that area will turn iron-brown in colour as well.
How to get rid off those reddish stains arround eyes?
Happy to announce that most tear stains can be simply prevented by keeping the face meticulously free of porphyrin-containing tears (if there are no health issues or breed issues). That means keeping the face hair trimmed, and wiping the face at least twice daily with a slightly damp wash cloth, to dilute out and wash away the tears. Or, if you want to get really fancy, cleaning under the eyes with ordinary contact lens cleaning solution (containing dilute boric acid, that oxidizes the iron in the porphyrins and lightens the color) will help keep things neat and tidy.
While you take wipe the your white fur babe face twice daily, please check possible options below that can cause excessive tears effect (information prepared using this AKC article about dog tear stains).
Examine the quality of your food. Probably you have heard few times from other white fur dog owners that a high-quality, grain-free diet works best. The corn, wheat, and meals that are used as fillers in inferior-quality foods just don’t ensure long-term good health and can cause allergic reactions, resulting in excess tearing and other problems.
Examine the quality of your water. Maybe home water is too poor or vice versa it has excess minerals. Its best to use purified, distilled, or reverse-osmosis water sources.
By the way, it is known that white fur dog food and water should not be served to plastic or metal bowl.
I have started to wipe my girls face few times a day. We have problem only with one eye. Its been a long time. Vets never found anything suspicious, I give her high quality grain free food, there is no problems with water or bowls for a long time already. So lets hope its only excessive tears that is common for her, and I need to keep it dry and clean not to get reddish eye.
Whats your story? Ware you able to solve it?