1. Hereditary causes
Primary excessive tearing in Bichon Frises can be hereditary. When tear production is naturally too heavy, tear stains are more likely to appear.
2. Inflamed tear glands
If the tear glands become infected, they may produce an abnormal amount of tears. When the tear duct cannot drain the extra fluid in time, the tears overflow and gradually leave visible stains.
3. Ear canal infections
Bacterial, viral, fungal, or parasitic infections in the ear canal, as well as swelling, pain, or itching in the ears, may cause the dog to scratch frequently with its hind legs. This irritation can also stimulate tear production.
4. Blocked tear duct
If the nasolacrimal duct becomes infected, inflammation and swelling can block the entire passage. Tears then fail to drain normally and overflow from the eyes, eventually creating tear stains.
5. Ingrown eyelashes
When the eyelashes grow inward, they constantly rub against the cornea. This makes the eye very uncomfortable, so the dog may paw at its face often and appear teary-eyed. Severe tear staining can follow.
6. Entropion
Entropion means the eyelid rolls inward, which also causes the lashes to irritate the cornea. This makes the dog extremely uncomfortable and leads to frequent rubbing of the eyes and heavy tearing, often resulting in pronounced tear stains.