Canine Discoid Lupus Erythematosus (DLE) may be most common immune-mediated skin disease we see. DLE is localised to the bridge of the nose, the front of the nose, and in some cases may extend further up the skull to affect the area between the eyes and the forehead, and even as high as the exposed parts of the ears. The disease does not extend beyond these regions and will not affect the remainder of the body.
The damage to the skin results initially in loss of pigment of the nose, followed by intense redness and scaling. As the lesions progress, ulceration and crusting develop.
Cause and animals predisposed
The cause of DLE is unclear. It has been proposed that in genetically predisposed dogs, solar radiation induces and inflammatory cascade that damages the outer layers of the skin, provoking a localised, chronic, immune-medicated reaction. The disease is more common in sunnier climates, indicating that the disease is either induced but certainly exacerbated by UV light exposure.
Breeds affected include Shetland sheepdogs, Collie breeds (Rough Collie, Border Collie, and other Collie breeds), German Shepherds and Siberian Huskies. Females are more frequently affected than males.
Diagnosis of Canine Discoid Lupus Erythematosus
The clinical appearance and history, and the fact that the remainder of the body is unaffected gives a strong clue that a dog may have DLE. There are quite a few conditions that affect the same body region so it is important to distinguish DLE from these to ensure a good response to treatment. For definite diagnosis, biopsy (collection of a small skin sample) under a short sedation is required.
Treatment of DLE
The prognosis in DLE is good, and in most cases, effective control is achieved without the use of potent immunosuppressive medications.
Avoidance of UV radiation exposure is essential – sunscreen cream can be used on the nose and sun-visors can be used as humans would use them. Yes, they can work very well!
Some clinicians will use oral corticosteroids initially at high doses for up to one month to bring the condition under control. Traditionally, the antibiotic Doxycycline, combined with Vitamin B3, has been very effective, however we need to be increasingly careful with overuse of antibiotics (to prevent antibiotic resistance) so this combination is becoming less relied upon nowadays.
Vitamin E oral capsules can be very effective as an anti-inflammatory, and essential fatty acid supplementation with oral Omega 3 and 6 oils are very useful.
Topical creams of Tacrolimus can be very useful, and sometimes patients benefit from short-term use of topical corticosteroid creams.