Literally, conjunctivitis means “inflammation of the conjunctiva”, that is, irritation of the transparent membrane that lines the inside of the eyelids and the white of the eye.
The dog’s eyes are very sensitive to the effects of external stimuli: dust, infections, etc. Therefore, inflammation must be treated quickly, as it causes soreness and can develop into other more dangerous eye diseases. As you guessed, the causes of conjunctivitis are quite diverse.
Simple conjunctivitis is manifested by redness and soreness of the eye itself and the inner surface of the eyelids, which are accompanied by more or less transparent expirations, which can also be caused by infection. One or both eyes may be affected, but more often the disease is of a benign nature.
Infectious conjunctivitis. Some microorganisms can cause conjunctivitis in dogs. But often inflammation of the mucous membrane is the first symptom of any viral infection, and has more serious consequences for a young dog in which a virus or bacterium acts on the entire body of a small animal. Thus, problems with the dog’s eyes may indicate such viral diseases as: early stage carnivorous plague, canine herpesvirus, rotavirus, coronavirus, dog adenovirus. Bacteria (some staphylococci and streptococci) and obligate intracellular parasites (chlamydia, mycoplasma) they can also cause conjunctivitis or complicate inflammation of the conjunctiva, creating superinfections for a second time.
Conjunctivitis caused by a foreign body or injury. Injury of the conjunctiva with claws or any other foreign piercing or irritating objects (such as twigs, small plant particles or dust) can cause soreness and inflammation of the eyes. In summer, it is especially necessary to avoid areas teeming with spikelets, which can get and get stuck in your dog’s eyes, causing damage, irritation, as well as inflammation.
With weak tear production, your pet’s eyes undoubtedly become more vulnerable to external stimuli (dry eye syndrome or dry keratoconjunctivitis). Insufficient amount of tears can no longer effectively remove the dust that naturally accumulates on the surface of the eye and damages it. But constant dry eyes and conjunctivitis can thus indicate neurological or metabolic diseases (carnivorous plague, diabetes mellitus, hypothyroidism, Cushing’s disease), as well as be a side effect of the action of certain medications.
Violations of tear production may also be associated with changes in the lacrimal gland itself or with obstruction of the tear ducts.
Blockage of the tear ducts. We are talking about small channels that come out of the inner corner of the eye and end in the nasal cavity, allowing an excessive amount of tears to flow out. Untimely care for excessively watery eyes leads to bacterial contamination and inflammation of the eye structures.
Allergic conjunctivitis. Very often, this type of conjunctivitis occurs due to an inflammatory reaction upon contact with environmental allergens (dust, pollen, mites) and begins on both eyes simultaneously (bilateral conjunctivitis of allergic origin), and disappears when the animal loses contact with the allergen (for example: if an allergy to pollen, it disappears at the end spring). In this case, it is possible to reduce the level of manifestation due to the comprehensive treatment of allergies. Also, sometimes food allergies and hypersensitivity to any component of eye ointment or drops can cause conjunctivitis.
Conjunctivitis caused by defects in the structures of the eye. Some dogs may suffer from inversion or eversion of the eyelids. In this case, the mucous membrane lining the eyelids becomes more susceptible to environmental aggression (dust, wind…) and exposes the animal to recurrent conjunctivitis. Plastic surgery of the eyelids allows you to correct this problem. This anomaly occurs in those dog breeds that have a lot of loose skin near the eyes (for example: basset Hound, Cocker spaniel, bloodhound, St. Bernard, Clumber spaniel, pugs, sharpies, French bulldogs and others). Improper eyelash growth also irritates the cornea and conjunctiva. This anomaly is quite common among such breeds as the American Cocker spaniel, the long-haired dwarf dachshund, the miniature poodle, small-sized brachycephals (Shih Tzu, Lhasa Apso and Pekingese), as well as the straight-haired retriever.
More complex causes of conjunctivitis in dogs
1. Corneal ulcers (these are corneal wounds accompanied by the disintegration of the surrounding tissue). They are often caused by a claw blow, a bush or another piercing object, less often by viral diseases and without treatment become very painful for your dog. With eye discomfort, the animal tends to injure itself, putting all its efforts to get rid of it, thus making the irritation even stronger. Therefore, a simple problem quickly becomes very serious. Only your veterinarian can detect a corneal ulcer invisible to the naked eye.
2. Keratitis (inflammation of the cornea).
4. Intraocular disorders such as glaucoma or uveitis.
The most common signs:
– redness of the conjunctiva, crying eye (serous or mucopurulent discharge), hypersensitivity to light (partially or completely closed eyelids);
– swelling of the conjunctiva.
Redness of the eye most often indicates the presence of conjunctivitis. However, a mandatory ophthalmological examination by a veterinarian is required to make sure that this is really conjunctivitis, and not changes associated with intraocular pathologies. If the diagnosis is confirmed, then the purpose of an ophthalmological examination is to determine the cause of conjunctivitis: the search for a possible foreign body, anomalies of implantation or orientation of eyelashes, initial eye diseases (glaucoma, uveitis), allergies, viral infection…
Only after an ophthalmological examination and additional diagnostic examinations (which will determine the cause of this ailment) your veterinarian will prescribe the right treatment.