Most people with white dogs get real annoyed with the reddish stains on their dogs face. The stains are caused by porphyrin, a chemical that occurs naturally in the tears and saliva in dogs. When this chemical is exposed to light, it stains white hair red. When dogs have excess tear production, plugged lacrimal (tear) ducts, the tears stream down the face and stain the hair. Dogs with allergies that chew or lick their feet will stain the hair on their paws red. If your dog suddenly starts excess tearing, make sure they are examined by your veterinarian to rule out problems such as infections, corneal ulcers and entropions (where the eyelid rolls in and rubs on the eye.)
Treatments used to decrease the staining include antibiotics (tetracycline and tylosine) given to the dog orally. These drugs somehow change the chemical of the porphyrin and decrease the staining. They do not decrease the tear production. The product called “Angel Eyes” contains tylosine as the main ingredient. Because these medications are antibiotics, veterinarians do not like to use them long term because of the possible impact on the liver, drug resistance and the effects on the naturally occurring gut flora in the intestinal tract. These medications are best used for a few weeks at the lowest dosage until the tear staining decreases. The effects can last for a few weeks then you can re-start the medication. It is best to use the medications in a pulse therapy, (once or twice a week) to change the chemical component of porphyrin and keep the tear staining to a minimum.
Some of the doses are listed below
1 – Tylosin 1/8 tsp on food SID (once a day) (just a pinch)
2 – Tetracycline: if <10-15lbs 25-100mg, if >15lbs 250mg BID(twice a day) x 1wk then 1 dose 2xweekly
3 – doxycycline 25-50mg SID
Another post I came across is using parsely flakes on the dogs food daily. I haven’t tried this myself, so I am curious if anyone else has had some luck with it.
Debra Garrison, DVM