Yes, cats do get sunburned sometimes. We see this quite a lot on the Internet and it is particularly relevant at the moment in many parts of the world where it’s very hot. The interesting aspect of domestic cats getting sunburned is that it almost exclusively occurs on the ears because they are sparsely protected by fur.
And what happens is that the ultraviolet light emitted from the sun, which is made up of UVA and UVB, penetrates the skin and causes damage to the DNA in the cells of the skin. UVA penetrates deep into the skin i.e. the dermis, while UVB penetrates into the epidermis i.e. the top layer of the skin. UVB is responsible for sunburn.
This ultraviolet light kills cells by damaging the DNA. Ultraviolet light creates a reaction between two molecules of thymine. Thymine is one of the bases that make up DNA. The reaction creates thymine dimer which is stable but the damage can be repaired. The more exposure to UV light that occurs, the more thymine dimers are formed in the DNA which makes it harder to repair.
If it can’t be repaired the cell cannot carry out its normal function. If the damage is too bad cancerous or precancerous cells are created from healthy cells. If the damage is too extensive a gene product called p53 programs the cell to die. If the damage is fixable, p53 instructs repair to take place.
And so, cancerous cells are then created because of DNA damage and in domestic cat this happens in the ear flaps. At this point, there may have to be a partial or complete amputation of the ear flaps. And that’s why you see cats with no ears on the Internet. It’s either sunburn or frostbite. They are at opposite ends of the spectrum and the ears are an extreme appendage which are the most susceptible to damage like this.
As you can imagine, white cats are particularly susceptible to sunburn of the ears because not only is the fur very thin over the ear flaps, there is no pigmentation in the individual hair strands to help block the sunlight because of the presence of the dominant white gene. Bicolor cats – white and another colour – are also susceptible (caused by the piebald gene). So, the sun directly hits the epidermis.
And as domestic cats, through their inheritance from the Wildcat, like warmth they can sometimes be in the sun for too long not realising the damage it can do.
It can take quite a few years for UV damage to become visible but once the early stages of cancer set in an urgent trip to a veterinarian is required.
If cancerous ear flaps are not dealt with, sometimes by an amputation, as mentioned, the cancer can spread to the rest of the cat resulting ultimately in a slow and painful death.
It perhaps goes without saying that the way to prevent this happening is for the cat’s owner to be aware of the dangers of bright and persistent sunlight and keep their cat indoors when the sun is at its hottest say between 10 AM and 3 PM. People can use sunscreen on their cat’s ears as they do on themselves (available on Amazon) but it might be best to consult with your veterinarian at the next visit.
Domestic cats instinctively find shade if it too hot and therefore provide plenty of shady areas for your cat outdoors if they are not already there naturally.
The picture on this page of a rescued cat called Fluff he was brought to Cats Protection at their Bridgend centre where he had to have his ear flaps removed. He was subsequently rehomed.
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