Q: Jersey, my 6-year-old Dalmatian, has a mostly white face with only sparse hair on his muzzle, so he often gets sunburned. Can sun cause skin cancer in dogs the way it does in humans?
A: Yes. Excessive sun exposure can cause a variety of skin problems in dogs, including cancer. Like humans, dogs can form actinic keratosis (AK), a firm, thickened, crusty skin lesion that may progress to skin cancer.
The most common canine skin cancer caused by excessive sun exposure is squamous cell carcinoma (SCC). When the ulcerated plaques are traumatized, they bleed or ooze a straw-colored liquid. Fortunately, SCC rarely metastasizes to other parts of the body.
Chronic exposure to sunlight also may give rise to hemangioma (HA) or hemangiosarcoma (HSA) of the skin. “Hem” refers to blood, “angio” to vessels, and “oma” to a mass. Hemangioma is a benign tumor of blood vessels, while hemangiosarcoma is the malignant version of this tumor.
Early on, HA’s are small, flat, red or purple discolorations of the skin. They may grow into large nodules that ulcerate and bleed. An AK or HA may progress to a malignant HSA. As with other sun-induced skin problems, most HSA’s occur as multiple lesions.
To prevent pre-cancerous skin conditions and skin cancer, minimize Jersey’s exposure to the sun, particularly during the late morning and early afternoon. Protect his skin with pet or human sunscreen and a shirt.
Editor's Note: With warmer weather around the corner, please keep your pets safe from heat exposure in cars.
Lee Pickett, V.M.D. practices companion animal medicine in Pennsylvania. Contact her at firstname.lastname@example.org.
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