Twospot is Bill and Joan Voss’s good old dog who now wears a T-shirt every day because of her recurring (and now permanent) sunburn injuries. T-shirts work well on most dogs. You can generally find a T-shirt about the right size for any dog that’s prone to sunburn… and if you can’t, then a little work with the old Singer can pretty easily modify something from the shop into something that does the job.

It is widely accepted that sun exposure is a contributing factor in the development of skin cancer of humans. Recent increases in incidence of skin cancer in our society have been blamed on a combination effect of excessive sun exposure and stratospheric ozone thinning. This also is the case in pet animals, particularly those that have some white coat or unpigmented (pink) skin. UV damage causes what are called actinic keratoses in the skin of lightly pigmented dogs. These actinic keratoses most often look like nasty, itchy and infected patches of inflammed skin.

Early sunburn damage lesions can sometimes regress with careful treatment. Part of the careful treatment required is close attention to prevention of continuing (further)UV exposure. However, it is a fact that actinic keratoses are also pre-malignant lesions that are capable of becoming invasive cancers. Most information about sunburn in pets concentrates on the increased risk of UV damage in summer months when the sun is most fierce. It is true enough to say that the sun is strongest in summer, but we paradoxically find that our worst cases of pet sunburn often actually occur in winter. This is because when it is cooler, some pets go to a lot of time and trouble seeking the sun warmth and then basking in it for excessively prolonged periods.

It is important to realise that there are two types of ultraviolet radiation in natural sunlight:

• UVA – this accounts for approximately 90% of ultraviolet radiation. It is thought to potentiate the carcinogenic effects of UVB.

• UVB – this accounts for approximately 10% for ultraviolet radiation. It is believed to be the primary carcinogenic form of UV radiation.

It is also important to be aware that the protecting creams that are available to reduce the damage caused by the sun fit into one of two categories.

• SUNBLOCKS (eg Zinc oxide). These are opaque and reflect or scatter the ultraviolet radiation. As ultraviolet radiation is reflected it may be redirected to surrounding tissues initiating or exacerbating sunburn. Sunblocks are less cosmetically acceptable and smearing or scratching to the area may compromise the protection given to that site. They may also be transferred from the animal to clothing, furniture, etc. as the animal rubs, leaving greasy stains.

• SUNSCREENS (eg paraminobenzoic acid (PABA), cinnamates and benzophenomes) These contain one or more chemicals which effectively absorb ultraviolet radiation. Sunscreens are invisible on the skin and are not greasy. PABA agents may cause allergic dermatoses, cinnamates are less likely to do this.

SUNSTOP is the first sunscreen on the market for pets. It contains oxybenzone and octyl methoxycinnamate which sink into the skin, effectively absorbing UVB and greater than 50% of UVA radiation. Both these products are considered safe and effective by the OCY Sunburn Treatment and Prevention Drug Review Board of the FDA. Sunstop can be applied to the head, paws legs and abdomen – basically anywhere where there is unpigmented skin. It can be applied without fear of an affectionate animal rubbing against legs, clothing or furniture leaving unsightly greasy marks.

The big difference between human sun protection creams and those for dogs and cats is that pets will (one way or another) ingest a lot of what you apply to their skin. To be useful as a pet animal sun protector, the stuff has to be effective and safe despite this very significant constraint. Come on down to the clinic if you want to know more and want to see what’s available.