Distichiasis and Ectopic Cilia

Rhea V. Morgan, DVM, DACVIM (Small Animal), DACVO

BASIC INFORMATION TREATMENT AND FOLLOW-UP Description Normal eyelashes develop from hair follicles on the skin surface Treatment Options of the eyelid. Distichia and ectopic cilia are eyelashes that grow No treatment of distichiasis is needed in dogs that are asymptomatic from small glands in the middle layer of the eyelid. Distichia grow (including most American cocker spaniels). If only a few distichia or out the duct of the gland and point downward or upward from the only minor signs are present, then topical lubricant ointments may be smooth edge of the eyelid. These cilia may brush against the cor- used to coat the cilia in oil and protect the cornea. If signs resolve, nea as the lids open and close. Ectopic cilia exit from the conjunc- then this therapy may be continued indefinitely. Temporary plucking tival or inner surface of the lid and point directly at the cornea. of the eyelashes is not usually performed, because they invariably Ectopic cilia most often develop on the central upper eyelid and grow back. may occur alone or in combination with distichia. Ectopic cilia Multiple distichia are often treated with cryotherapy, which is may arise in just one eye, but it is common for distichia to be found the application of a freezing agent to the underside of the eyelid, in both eyes. over the affected gland. Affected glands may also be cauterized, Causes but the heat generated by cautery often damages surrounding tis- Distichiasis may be inherited. It is common in certain breeds sues more than freezing does. Surgery to remove the hairs is not of dogs, such as the American cocker spaniel, shih tzu, often performed unless only one or two clusters are present. Bedlington terrier, boxer, Weimaraner, Shetland sheepdog, col- Ectopic cilia are best treated by surgical removal of the cilia lie, Pekingese, and others. Purebred dogs are affected more and the associated eyelid gland. Because these lashes are so small, often than mixed-breed dogs and cats. Ectopic cilia are less surgery may be performed under an operating microscope. It is common but may be found in all types of dogs, usually before important to remove these cilia as soon as possible, so that the cor- 1 year of age. nea is no longer irritated and pain is relieved.

Clinical Signs Follow-up Care Signs associated with distichiasis often depend on the number and Following distichia surgery, a topical antibiotic or lubricant may be character of the lashes present. American cocker spaniels often applied to protect the cornea, because eyelid swelling is common for have numerous distichia, but they are short and fine and often several days. An Elizabethan collar may also be applied to prevent cause no clinical signs. In other dogs, watery tearing, increased self-trauma. Dark eyelid margins may turn pink after they are treated mucus production, blinking or squinting, or conjunctivitis may be with cryotherapy, but the black color typically returns in 6-8 weeks. noted. Corneal ulcerations may occur in some dogs. After surgery for ectopic cilia, topical antibiotics and pain reliev- Ectopic cilia often cause corneal ulcers, marked squinting, and ers may be used for corneal ulcers, and an Elizabethan collar may be pain. Signs may improve for awhile if the conjunctiva grows over applied until the ulcer heals. Dogs are periodically monitored post- the eyelash, but invariably they return when the cilia grows longer operatively until the corneal ulcer and surgery site have healed. and becomes exposed again. The resulting corneal ulcer does not Prognosis respond well to medical therapy. No single procedure is effective for removing all distichia, because hair follicles are very difficult to kill. Some distichia can be expected Diagnostic Tests to persist or return. In addition, more distichia may grow in new Distichia can often be seen with the naked eye and a light beam locations over the course of months to years. Periodic monitoring focused on the eyelid, but ectopic cilia can be very difficult to see. for regrowth is warranted, and repeated treatments may be needed. Magnification is often needed to locate ectopic cilia. The cornea Many dogs with ectopic cilia are cured with one surgery, if the is often stained with fluorescein to determine the presence of an entire hair follicle and associated glands are removed completely. ulcer. The eyelids and surface of the eye are also examined for Any recurrence of clinical signs (especially pain and squinting) other defects. requires re-examination for regrowth or eruption of new cilia.