Six things I learned from Dr. Wilsons solar dermatitis Fetch dvm360 session

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During the recent Fetch dvm360 conference in San Diego, Laura Wilson, DVM, DACVD, stressed the importance of identifying predisposing factors and lesser-known signs of solar dermatitis. She also offered additional tips on nonsurgical treatment and prevention. Here are my key takeaways from her session:

1. White and hairless pets are not the only ones at risk. We know white skin and hairless skin are obvious predisposing factors for solar dermatitis, but animals with scarred, depigmented skin are also at risk of developing problems associated with sun exposure, Dr. Wilson says.

2. Altitude and environment matter. Pets that sunbathe in strong midday light receive lots of sun exposure, but so do animals living at higher elevations and those that hang out on white or light-colored concrete-consider those dogs that like to pace around the patio. Dr. Wilson notes that even indoor animals can be exposed to enough sunlight to cause malignant changes. 

3. Problems can start early. Although 6 years of age is the most common point when veterinarians see skin changes, Dr. Wilson has seen early signs of sun damage or disease in pets as young as 3 months old and carcinomatous changes as early as 3 years of age.

4. Signs of solar dermatitis can vary. Early signs of the condition can be as subtle as erythema and fine scaling before visible scabbing and peeling develop. In cats, advanced signs of the condition include folding of the pinna or flipping of the head from pain. In dogs, Dr. Wilson says advanced disease commonly presents as the characteristic up-and-down, bumpy texture you feel when running your hands over affected skin-the depressions are scarred areas and the elevations are active areas of inflammation.

5. Nonsurgical treatments can be effective. Besides surgical intervention, Dr. Wilson has used alternative treatments for solar dermatitis with some success. She's seen some benefit with topical B-carotene supplementation (vitamin A precursor), but she's cautious about using this supplement systemically. With smaller lesions she uses imiquimod cream (a retinoic acid also used for warts) to help stimulate the immune system in those regions. Since the ointment can irritate the skin, she suggests treatment every other day.

Dr. Wilson also utilizes pentoxifylline for wound healing and to increase blood flow into affected areas of the skin. In her experience, it produces few side effects even with long-term use. And finally, she uses a CO2 laser to ablate diffuse lesions such as comodomes, which helps exfoliate and expose normal skin.

6. Prevention is critical. Besides keeping pets out of the sun, it's important for clients to use waterproof sunblock (SPF 30 or higher) and solar suits to help protect pets' skin from sun exposure while still allowing them to roam outdoors. Although zinc toxicity is a common concern, Dr. Wilson says she's never seen problems resulting from sunscreen ingestion. She says a dog or cat would have to ingest a massive quantity (0.7 to 1 g/kg) to experience toxicosis, which is close to impossible with appropriate use.  

Dr. Jessica Nichols, BVSc, is an associate veterinarian at Countryside Veterinary Hospital in Valley Center, California.