Canine Uveodermatologic Syndrome
Also known as: UVD — Vogt-Koyanagi-Harada-like syndrome — VKH-like syndrome
Canine uveodermatologic syndrome is an autoimmune condition directed against melanin of neural crest (skin, hair, anterior uvea) and neuroectodermal (retina) origin.
From what is known in humans, it is thought that a cell-mediated hypersensitivity exists against melanin and melanocytes, and distinct subpopulations of cytotoxic T lymphocytes with activity against melanocytes have been identified.
The condition is reported most often in breeds such as: Akita, Australian Shepherd Dog, Beagle, Chow Chow, Samoyed, Siberian Husky, Alaskan Malamute and related crossbreeds.
Initial onset of lesions has been noted in animals ranging from 13 months to 6 years of age.
Ocular signs generally precede dermatological signs. Initially they consist of bilateral uveitis. Later this can progress to retinal detachment, posterior synechiae with secondary glaucoma and cataracts and a resulting blindness.
Skin and hair abnormalities: leukoderma and leukotrichia often involving the eyelids, nasal planum, lips, scrotum, vulva, footpads. Erythema, ulceration and crusting can also occur in the depigmented areas.
Pain and prutitus can occur and lymphadenopathy is common.
There is no specific diagnosis for UVD syndrome, but the clinical signs are suggestive. A thorough history should be taken and an ophthalmic and dermatological exam performed.
Histopathology should be performed on skin biopsies. Biopsies show lichenoid dermatitis, histiocytes, small mononuclear cells and giant cell infiltration. The level of melanin in the epidermis and hair follicles is decreased.
Differential diagnoses such as SLE, pemphigus foliaceus, pemphigus erythematosus, epitheliotropic lymphoma, vitiligo and leishmaniasis should be ruled out.
Topical treatment of the uveitis is indicated with corticosteroids and cycloplegics.
Systemic corticosteroids are also required to resolve the uveitis and dermatological lesions. Long-term therapy is usually required to obtain remission and the dose can then be tapered down.
Azathioprine can be used to lower the dose of corticosteroids, and might be used alone in some cases.
Systemic cyclosporin is used in humans and has been suggested as another possible treatment option.
In all cases, aggressive treatment is required and short-term success is usually good. However recurrence is common and lesions may never fully resolve.
Schaer, M. (2010) Clinical Medicine of the Dog and Cat Manson Publishing
Harvey, R. (2009) A Colour Handbook of Skin Diseases of the Dog and Cat Manson Publishing
Maggs, D. (2008) Slatter's fundamentals of veterinary ophthalmology Elsevier Health Sciences