Tear staining can be from many different causes. Also consult with your vet first. There are antibiotics the vet can prescribe that will help some cases of tear staining.
Here are a few other tips you can use to help with tear stain removal.
Use filtered or distilled water.
Using air purifiers (such as those you can obtain from EcoQuest) in the rooms with the dogs for air purity.
Ensure good ventilation by using exhaust fans, ceiling fans, open windows etc.
Ensure your Shih Tzu have adequate exposure to sun. Being outside with sunshine and clean fresh air is healthy for you and your pets.
Keeping your dogs clean with their hair out of their eyes is also important.
Keep your dogs environment clean.
Keep the filters in your air conditioning and heating systems clean.
Water and food bowls should be either ceramic, glass or stainless steel. I prefer water bottles.
At least once per month, the bowls can be soaked in a weak bleach solution and then washed with regular dishwashing liquid and air-dried.
Genetically, there are some bloodlines that are more prone to tearing then others. Hair growth on the eyerims.
Ask your vet for the antibiotic, Tylan. Tylan is primarily made to battle microplasma in poultry and swine. This is not a commonly used canine antibiotic so if desensitizing occurs towards Tylan, it is not as damaging as it could be with other more commonly used canine antibiotics.
Ask your vet to run a Culture and Sensitivity test on the tearing residue. Having the tearing cultured almost always is successful because the sensitivity report will tell your veterinarian what exact antibiotics the bacteria will respond to. You will need to consult with your vet about the Tylan and if he/she decides this is an appropriate treatment for your Shih Tzu, he is also able to figure out the correct dosage. Do not try figuring out the dosage yourself. Consult with your vet about the antibiotic, Tylan (or something else he/she may have found useful for tear stains) and follow vet's instructions about dosage and how to administer the drug to your Shih Tzu.
Try first to eliminate the cause by consulting with your vet regarding any issues your Shih Tzu may be experiencing that might be causing the stains. If the cause can be determined and the conditions remedied, the tear staining should slowly fade away.
There are ways to remove the stain once the staining has stopped. Some ways to remove the stain are harsh. Some products work for one Shih Tzu, and then not for another. You can experiment with all the different products on the market to see if any will work for your Shih Tzu. You can also try putting a little corn starch on a toothbrush, moisten the brush, and brush the stained areas daily. You can also cover up the stain with make-up especially for this purpose for dogs (which is what a lot of the Show Dogs end up doing).
Tearing can be related to a medical issue, with environment, care and genetics playing a part in the mix. Try to eliminate as many of the possible causes first. Then proceed to other methods of removing the stain.
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