The cause of tear staining is excess tearing. When the face hair is wet from excess tearing it is the perfect breeding ground for bacteria and yeast. One of the most common yeast infections is Ptyrosporin (Red Yeast) which causes a reddish-brown stain.
If you have a Maltese with excessive tear stains and tearing a visit to your veterinarian may be needed. It is not unusual to find that your Maltese may have completely clogged tear ducts. Dogs with smaller eyes tend to have worse problems with tear staining than dogs with larger eyes.
Ear infection can be the cause of excessive tearing and staining. To help avoid ear infections, the hair in the ears must be plucked and ears must be thoroughly dried after bath.
It is my opinion and experience that genetics plays the largest role in whether or not a Maltese has excessive tear staining. Again, good breeding is key and the larger eyes tend to produce less tear stain.
The water in many areas has a high mineral level. Providing your Maltese distilled water from a bottle will greatly reduce tear stains.
Feed only food and treats that are natural with no additives, preservatives or food color in it. Many commercial dog foods contain beep pulp which can cause staining of the face and beard.
Another potential source of tear staining is fleas because fleas need moisture to survive and get this from the dogs' tears/eyes. Naturally, this can cause an irritation. Another problem that comes with fleas is ear mites. These are carried by the fleas. Ear mites can cause severe ear infections and as a result tear staining. I recommend REVOLUTION for monthly treatment to prevent fleas, ticks, heartworm, and intestinal worms.
A ten day course of low dose chlortetracycline or tetracycline may help cure tear stain, however, do not use this in puppies that have not yet cut their adult teeth. Tetracycline has been shown to cause teeth which have not erupted to permanently stain yellow.
Tums is primarily a source of Calcium and giving your Maltese 1/2 of the Fruit flavored variety twice a day will help change the pH of the tears making it less friendly for growth of yeast and bacteria.
TYLAN is the brand name for Tylosin, a veterinary antibiotic that is FDA approved for fowl (chickens/turkeys) and swine (pigs). This is used primarily to treat respiratory disease caused by Mycoplasma gallisepticum. This product has been very successful for me personally and the before and after photo above was accomplished with a combination of Tylan and Boric Acid power.
Boric Acid eye wash such as Bausch & Lomb Eye Wash applied daily to the tear stain area will help with tear stain prevention and removal. Boric Acid is a natural anti-fungal and will also lighten the tear stains over time.