Blepharitis in Dogs – Causes, Symptoms and Treatment

What is Blepharitis in Dogs? 

Blepharitis refers to inflammation of the eyelid(s) and surrounding skin, resulting in swelling and discomfort. Dogs will often scratch or rub at their face as a result, which can lead to secondary trauma to the conjunctiva (the mucus membrane covering the inner eyelid and eyeball) or the eye itself. Blepharitis may occur due to several possible reasons. Treatment requires veterinary attention but will vary based on the underlying cause. 

Symptoms of Blepharitis in Dogs

The most common symptoms of dog blepharitis include: 

• Swelling or thickening (edema) of the eyelids
• Redness, flaking, and scaling of the skin around the eyelids 
• Loss of hair or pigmentation around the eyes
• Pain in the eye area, for example, squinting and excessive blinking
• Rubbing or scratching at the eyes
• Redness to the sclera (white of the eye)
• Conjunctivitis 
  
• Eye discharge (may be clear, mucoid, or purulent/green pus) 
• Papules or pustules (pimples) may be present around the eyelids in some cases 

What Causes Blepharitis? 

Anything that causes irritation of the eye can lead to blepharitis. Common causes of canine blepharitis include:  

• Allergies: Blepharitis may be caused by an allergic reaction to a bug bite or irritant that comes in contact with your dog’s eyelid. It may also be associated with allergies to food or something in the environment (atopy). 
• Infection: Bacterial or fungal infections can lead to inflammation of the eyelid. 
• Congenital abnormalities:  Breeds with excessive facial folds and short flat faces may be more likely to develop blepharitis. Certain breeds are also predisposed to several congenital eyelid abnormalities, such as entropion (in which the edges of the eyelid turn inwards) and ectropion (in which the edges of the eyelid droop outwards). Eyelash abnormalities such as distichiasis and ectopic cilia are also common culprits. 
• Growth or tumor on the eyelid: Growths can occur anywhere on a dog’s body, including on the eyelids. Common eyelid tumors include meibomian gland tumors, papillomas, and melanomas. Luckily they are often benign, and surgery can be curative. Meibomian glands can also become clogged, inflamed, or infected, appearing as a red or yellow bump on the eyelid, similar to a sty. 
• Parasitic blepharitis: Mites, such as Demodex or scabies, can cause hair loss around the eyes and blepharitis. 
• Other ocular or systemic diseases: Conditions, such as hypothyroidism, Cushing’s Disease, zinc-responsive dermatitis, and other immune-mediated conditions can also cause blepharitis, among other symptoms. Trauma or a foreign body in the eye are also possible causes. 
• Idiopathic: If no cause is identified, this is called idiopathic blepharitis 

How is Blepharitis Diagnosed? 

Your pet vet will diagnose this canine eyelid disease based on history, a nose-to-tail physical exam, an eye exam, and diagnostic tests. In addition to examining your dog’s eyelid, they will likely want to perform tests to make sure that the eye itself is not also injured. This may include: 

• Fluorescein stain: This test checks for the presence of a corneal injury or ulcer. A small amount of stain is applied to the eye, which will stick to areas of ulceration and glow under black light. 
• Schmear tear test: This test is used to measure tear production. It involves placing the tip of a special filter paper inside the lower eyelid and waiting for 60 seconds. 
• Tonometry: This test involves gently touching the surface of the eye with a Tonopen to measure pressures within the eye. Intraocular pressure may be elevated in glaucoma or decreased in uveitis. 

Additional testing for blepharitis may include: 

• Cytology and/or culture: Your vet may collect samples of cells or ocular discharge to look for evidence of abnormalities and infectious agents (bacteria, fungi, parasites) under the microscope. A culture can be used to grow the specific agent present and determine which medications it will respond to. 
• Biopsy: If a mass is present, collecting a sample or surgically removing the whole thing for evaluation may be recommended. 
• Bloodwork: Bloodwork can help evaluate your dog’s overall systemic health and major organ function.
• Allergy workup: If your vet suspects allergies, they may recommend a diet trial or allergy testing to evaluate for food or environmental allergies. 

What is the Treatment for Blepharitis in Dogs? 

The treatment for blepharitis will vary depending on the underlying cause. Surgery may be recommended to correct eyelid abnormalities or remove a mass, which is often curative. In the case of infection, you will be dispensed drops or ointment containing antibiotics +/- anti-inflammatories to apply to your dog’s eyes. 

Food allergies may be managed with a prescription hydrolyzed protein diet, and environmental allergies can often be managed with medications such as Apoquel, Cytopoint, steroids, antihistamines, or more. 

Additional measures such as applying a warm compress to the area, oral pain meds or anti-inflammatories, and an E-collar to prevent additional scratching and rubbing will often be recommended regardless of the cause. 

Is There a Cure for Blepharitis in Dogs? 

Often times blepharitis will resolve with treatment but may recur in the future, especially if it is caused by an underlying allergy. It is important to fully address the underlying issue. In some cases, such as surgical correction of an eyelid abnormality or removal of a tumor, a cure is possible. 

Luckily most eyelid tumors in dogs are benign, although some may be cancerous. In this case, additional treatment recommendations should be discussed with your vet.