Solar Dermatitis in Dogs

What is solar dermatitis?

Solar dermatitis is a skin disease caused by exposure to the sun. It occurs mainly in dogs with white or pale patches of skin (non-pigmented areas).

While any breed of dog can be affected, it is more common in white-haired, short-coated breeds such as the American Staffordshire terrier, bull terrier, boxer, Dalmatian, beagle, Australian shepherd, and whippet.

What are the signs of solar dermatitis?

Solar dermatitis often starts as skin redness (erythema) and excessive dryness (resembling a sunburn). As it progresses, the skin becomes crusted (scabby) and ulcerated. Sometimes, it may progress to a malignant tumor called a squamous cell carcinoma at the site. 

The most commonly affected areas in the dog are the flanks, groin, armpits, top of the nose, eyelids, the trunk (sides), and the outside of the legs. If the dog likes to lay more on one side, the side exposed to the sun is often more affected. 

How is solar dermatitis treated?

Treatment can vary, depending on the severity of the condition. Topical steroid creams, or oral steroid medications, are sometimes used to prevent discomfort and reddening. Other topical or oral medications, such as beta-carotene, acitretin, isotretinoin, vitamin A, and imiquimod (an immune stimulant) may also be used. If secondary skin infections occur due to the skin irritation, antibiotic therapy may be used.

How can I prevent the condition from worsening?

Keep your dog out of sunlight, ideally by keeping them indoors between the hours of 10:00 am and 4:00 pm on sunny days, because this is when ultraviolet (UV) light is most intense. Apply sunscreen to any affected and thinly-haired areas where the dog cannot easily lick it off. Some products may be toxic to dogs, so never use a human sunscreen without first checking with your veterinarian. You can also try covering your dog with a sunsuit or T-shirt when outside.

How do I know if my dog has squamous cell carcinoma?

If there is any concern that the condition may be progressing to squamous cell carcinoma, your veterinarian will recommend taking a tissue biopsy from the affected area (a surgical excision of a piece of the tumor). Most dogs need general anesthesia for this procedure. A biopsy is a surgical excision of a piece of the tumor. That sample is then examined by a veterinary pathologist under a microscope, a process called histopathology. Histopathology helps to make a diagnosis and can indicate how the tumor is likely to behave.