Discoid Lupus Erythematosus (DLE)

What is it?

DLE, also called cutaneous lupus erythematosus, is the most common form of lupus affecting only the skin in dogs; it is very rare in cats. The immune system attacks a layer of skin cells, so the surface sheds. The cause is unknown, but ultraviolet (UV) light worsens it and it is more common in sunny climates. It is seen more often in collies, Shetland sheepdogs, German shepherds, and Siberian huskies, although it can occur in any breed. It is considered a relatively benign autoimmune disease.

What signs should I watch for?

The nose typically loses pigment, and its normal bumpy, cobblestone texture becomes smooth and flat. Erosions, sores, scaling, and crusts develop. Lesions may spread to the skin around the eyes and lips, the ear flaps, and rarely the genitals or the whole body. Because the nose has a rich blood supply, sores near a larger vessel can bleed heavily. Some dogs are bothered by it, while others seem unaffected.

How is it diagnosed and treated?

A skin biopsy is needed to confirm DLE; for the nose and face this is usually done under sedation or anesthesia. Treatment suppresses the immune reaction, often starting with steroids such as prednisone or dexamethasone, with stronger immune-suppressing drugs if needed and antibiotics or medicated care for secondary infection. Your veterinarian will tailor the plan.

Can it be prevented, and what's the outlook?

• Because UV light worsens DLE, ask your veterinarian about limiting your dog's sun exposure.
• Autoimmune skin disease is rarely cured, but it is usually well controlled with the right medications.