Discoid Lupus Erythematosus (DLE), also known as Collie Nose, initially appears as pigment loss, redness and scaling of the nose – later followed by ulceration, erosion and crusting. With time, lesions may become more extensive and spread up the bridge of the nose. Less commonly, lesions affect the eyes, ears, lips, and genitals. This disease is an auto-immune skin disorder. In DLE, normal immune defense mechanisms (antibodies) inappropriately attack the skin cells in specific areas of the body. This can lead to significant damage of the tissue. DLE is very rarely seen in cats.
DLE is usually first noticed by the owner when the nose loses its normal pigment and texture. The tissue will become pale pink or blue, smooth, and shiny before developing ulcers that may crack and bleed. The lesions may also involve the other tissues listed above. Exposure to sunlight will exacerbate the condition. In fact, DLE may be seasonal and related to ultraviolet radiation exposure during the summertime.
Some dogs may paw at the lesions or rub the muzzle and face on the floor, while others do not seem to be bothered by the condition. Self trauma usually occurs after ulcers form and crack open.
All Shepherd and Collie breeds, Huskies, Brittany spaniels, and German shorthaired pointers, both males and females, have a genetic predilection to developing DLE. Chronic DLE lesions have an increased risk of becoming malignant, turning into squamous cell carcinomas.
There are other diseases that cause lesions and symptoms similar to those seen in DLE. Extensive testing may be required to rule out ringworm, cutaneous lymphoma, pemphigus foliaceus, and other problems that can resemble DLE. Ultimately, a tissue biopsy is most helpful in achieving a definitive diagnosis.
Treating DLE may be as simple as avoiding prolonged exposure to sunlight and applying a non zinc-based sunscreen during outdoor activities. For more severe cases, topical and systemic immunosuppressive medications like prednisone may be necessary to clear up the lesions. Doxycycline is also commonly prescribed. This drug possesses antibiotic as well as immuno-modulating properties useful for treating DLE. Doxycyline is typically combined with niacinamide, a Vitamin B derivative, to treat autoimmune type skin disorders. To prevent recurrence, all dogs with a history of DLE should avoid excess sun-exposure.
The prognosis for Discoid Lupus Erythematosus is generally good when treated appropriately. There are no systemic effects associated with DLE.