Congenital Alacrima: No Tears to Shed

Causes of keratoconjunctivitis sicca (KCS) include infectious disease, such as distemper; toxicity due to sulfonamides or other drugs; surgical removal of the gland of the third eyelid; facial trauma; and congenital alacrima. This article describes clinical findings and treatment outcomes for 16 juvenile Yorkshire terriers suspected of having severe unilateral KCS due to congenital alacrima. Each patient evaluated in this study had a long-term history of severe, unilateral blepharospasm and variable amounts of mucoid discharge from and over the surface of the affected eye. None of the dogs had responded to various topical ophthalmic antibiotics; they had not been treated with sulfonamides, had not had surgery involving the third eyelid gland, and did not have a history of trauma or infectious disease. Blepharitis, mild conjunctival hyperemia, and varying degrees of superficial corneal vascularization with a dry appearance to the ocular surface were presenting signs in the affected eyes. History, signalment, clinical signs, age at presentation, disease severity, and lack of response to medical treatment all suggested that the cause of KCS in these dogs was aplasia or hypoplasia of the lacrimal gland. All but one of the affected dogs evaluated in this 4.5-year period were Yorkshire terriers, suggesting a predisposition to this syndrome. In addition, females (n = 12) were 3 times more common than males (n = 4). Based on information summarized for the cases presented in this article, congenital aplasia or hypoplasia of the lacrimal gland should be considered when a young, small-breed dog is presented with signs of severe, unilateral KCS. Lack of trauma, infectious disease, toxicity, or previous surgery of the third eyelid is supportive of this diagnosis.

COMMENTARY: Such medications as cyclosporine and tacrolimus have revolutionized treatment of KCS in the past decade. However, this paper succinctly points out that not all KCS cases respond to medical treatment. Although cyclosporine 0.2% ointment provided some palliative relief for these patients, it did not increase tear production. Functional lacrimal glands are required for this class of medications to be effective. Histologic examination indicated that either unilateral aplasia or hypoplasia of the lacrimal glands was present.

The possibility of congenital disease should be considered when young, small-breed dogs present with unilateral KCS, frequently of rapid onset. This author has seen congenital, juvenile-onset KCS in cavalier King Charles spaniels, Shih Tzus, Lhasa apsos, and Chinese crested dogs in addition to Yorkshire terriers. In my experience, hypothyroidism should be suspected as the cause of acute-onset unilateral KCS in adult dogs.

Severe, unilateral, unresponsive keratoconjunctivitis sicca in 16 juvenile Yorkshire terriers. Herrera HD, Weichsler N, Rodríguez Gómez J, García de Jalón JA. VET OPHTHALMOL 10:285-288, 2007.