Distichiasis or extra eyelashes is a common condition in dogs.
It occurs when eyelashes develop in an abnormal location, emerging from the eyelid margin rather than the eyelid skin. In many dogs the hairs are soft and cause no problem but in some cases irritation from these hairs can cause discomfort, and in severe cases they can damage the surface of the eyes to cause corneal ulcers. This requires specialist veterinary ophthalmology services.
Aberrant hairs can occur in any breed of dog but are most commonly seen in the American Cocker, Bulldog, Cocker Spaniel Poodle, Dachshund and Weimeraner breeds.
What are the signs of distichiasis?
In many dogs the extra eyelashes do not cause a problem, but in some cases they can rub the surface of the eye and cause irritation. The most common signs that you will notice are increased blinking/squinting of the eye, increased watering, and redness of the ‘white’ of the eye.
What are the treatment options for distichiasis?
Distichiasis only requires treatment if the hairs are causing irritation, conjunctivitis or corneal ulceration. There are a number of treatment options:
- Ocular lubricants – twice daily use of a lubricating gel or ointment will improve the tear film and may reduce irritation in mild cases. Lifelong treatment will be required.
- Plucking – the extra eyelashes can be plucked using epilation forceps. This is also useful to prove the cause of irritation. Epilation is a temporary treatment and will need repetition every 4-6 weeks for life.
These treatments require a general anaesthetic, and rely on an assumed location of the hair follicle and so do not have 100% success rate. They can cause some scarring and depigmentation of the eyelids but this is usually temporary.
- Electrolysis – a fine electrode is inserted into each gland opening alongside the emerging hair. A current is applied to attempt to permanently destroy the hair follicle preventing regrowth of the distichia. Only those hairs present at the time of treatment can be identified and treated, so new hairs may emerge at a later date and cause irritation. The procedure can be repeated a number of times if necessary.
- Cryotherapy – this technique can be useful when many hairs are present. A probe is applied to the inner surface of the eyelid in the region of the hair follicles and the eyelid is then frozen to destroy the hair follicles. This procedure may also need to be repeated, and has a similar success rate to electrolysis, however, the swelling immediately post-operatively is greater.
Surgical approaches are typically reserved for severe cases or those in which the above procedures have been unsuccessful. Techniques involve surgical dissection to permanently remove the hair follicles, or creation of outward turning of the eyelid margin in order to direct the hairs away from the surface of the eye.
This image shows distichiasis in a Labrador retriever. The aberrant hairs emerge from the eyelid margin in both upper and lower eyelids
Ectopic cilia are another form of aberrant hair growth but in this case, instead of emerging at the eyelid margin, ectopic cilia emerge through the conjunctiva on the inside of the eyelid to directly contact the cornea.
Ectopic cilia typically occur in young dogs. They tend to be extremely painful and often cause corneal ulcers, which can resolve between hair cycles (every 4-6 weeks).
Although very painful, ectopic cilia are very small and difficult to see without specialised equipment.
The image on the left shows ectopic cilia emerging from the inside of the upper eyelid.
What treatment is available for ectopic cilia?
Treatment for ectopic cilia involves surgical removal of the hair plus its associated follicle, with the wound left to heal by scarring. Provided the entire follicle is removed the hair will not regrow. Any associated corneal ulceration heals rapidly after surgery, provided no secondary infection has occurred.
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