Collie Nose (Nasal Solar Dermatitis)
This is a weepy, crusty dermatitis that affects Collies, Australian Shepherds, Shetland Sheepdogs, and related breeds. In the US it is seen most commonly in sunny regions such as Florida, California, and the mountainous regions of the west.
Initially, the skin appears normal except for the lack of black pigment. With exposure to sunlight, the skin at the border between the muzzle and nose becomes irritated. As the irritation continues, hair falls out and the skin begins to ooze and crust. With continued exposure, the skin breaks down. In advanced cases, the whole surface of the nose becomes ulcerated and the tip itself may disappear, leaving unsightly tissue that bleeds easily. Skin cancer may develop.
This condition is caused by lack of pigment on the nose and prolonged exposure to the ultraviolet rays in sunlight. Lack of pigment is hereditary in some dogs, but it can be acquired through skin diseases and scarring.
Nasal solar dermatitis must be distinguished from discoid lupus erythematosus, pemphigus foliaceous, and zinc responsive dermatosis. All 3 diseases produce a skin reaction similar to nasal solar dermatitis. A distinguishing feature of nasal solar dermatitis is that pigment was lacking before the disease developed. In the other 3, the pigment disappears as the disease progresses. Note that once depigmentation occurs in dogs with these diseases, the damaging effects of sunlight add to the problem.
Treat an irritated nose with a skin preparation such as Cortaid that contains 0.5 to 1.0% hydrocortisone.
This is a genetic condition. Prevent further exposure by keeping you dog indoors as much as possible when the sunlight is the most intense. Letting your dog out on cloudy days does not address the problem, because UV rays still penetrate the clouds. Sunscreens are of some aid in protecting dogs who spend time outdoors. Use products containing an SPF greater than 15. Apply the sunscreen 30 - 60 minutes before exposure and again later in the day.
Please contact your veterinarian if you have questions regarding this condition.
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