Stop Sunburn in Horses

Sunburn in Horses

• Like humans, sun damage is a real threat to horses, and not only for their cute muzzles.

• Most gray and white horses are sensitive to the sun. A true white horse will have pink skin, and a gray horse will have black skin. You need to worry about the pink skin on all colors of horses as this increases the risk of sunburn.

• The pink skin under white hair is unpigmented, thus missing some vital natural melanin. The melanocytes in the skin produce melanin, a pigment that darkens the skin and absorbs UV rays before they reach deep into the skin and cause damage to the DNA of cells, which can trigger cancers like squamous cell carcinoma.

• Overexposure to the sun’s UV rays isn’t canceled out by melanin – sunburns and photosensitivity can still happen.

• All breeds of horses are susceptible, although white markings are more likely to suffer in the sun’s rays.

• Darker skin can still experience sunburn, especially if the coat is thin, clipped, or missing patches of hair. Some horses may develop sores or dramatic skin damage from too much sun.

Don’t forget about under the chin – a dollop of sunscreen will do the trick!

Sunburn vs. Photosensitivity

Horse skin is at risk from UV light in a few different ways.

Sunburn

• Sunburn happens from direct exposure to UVA and UVB rays that enter the skin and create damage inside the cells. As a response, the cells send out an alert via inflammatory mediators, which trigger the body to send more blood flow to the area, hence the red color of a sunburn. There’s also more warmth to the area from that increased blood flow.

• The damaged cells need to heal, and in the meantime, can peel, blister, and otherwise become a painful problem.

Primary photosensitivity

• And what the heck is photosensitivity? This is a phenomenon that can happen in one of two ways.

• Primary photosensitivity is when a plant creates a skin reaction in non-pigmented skin with sun exposure. If your horse eats or touches buckwheat, alsike clover, perennial rye, St. John’s Wort, or any number of other plants, the plant’s phototoxic ingredients enter the bloodstream, and when exposed to UV light, damage the skin cells that are unprotected by melanin.

Another type of photosensitization

• Secondary photosensitivity results from liver damage. When horses eat plants, the chlorophyll in those plants metabolizes, and one of the by-products is phylloerythrin. When liver diseases interfere with this process, the phylloerythrin isn’t properly processed and can accumulate to toxic levels, triggering photosensitivity.

• It’s sometimes hard to discern if sunburn is regular, old ultraviolet light exposure, or if a horse’s liver has a role in the process. It’s also worth noting that some mud fever cases are actually photosensitivity.

This article has great photos of plants known to trigger photosensitivity in horses.

What harm does sunburn cause in horses?

• Aside from pain, blisters, and peeling, sun damage interferes with the immune responses of the skin, creating vulnerability for skin infections like mud fever or rain rot. The pain can also cause head shaking or head shyness and develop into skin cancers.

Treatment and Prognosis for Sunburn in Horses

• It’s often tricky to distinguish sunburn from photosensitivity, but horses with a sudden case occurring in typical situations are a clue that there’s more than just sunburn.

• Enlist your vet’s help to treat the area with topical medications and possibly antibiotics. Sunburn is painful and may warrant some anti-inflammatory pain medications.

• Your vet should look around your horse’s paddock for weeds and other things that trigger redness and blisters. They may want bloodwork to check your horse’s liver for conditions that create secondary photosensitization.

• Anything that doesn’t clear up in a few days by being clean, dry, and covered warrants a call to your veterinarian.

What ointment is good for sunburn in horses?

• Your vet can suggest the best ointment to treat sunburn, and it might be as simple as a zinc oxide cream like diaper cream. Other prescription medications, like silver sulfadiazine cream, are fantastic for burns. These will add a little UV protection, too.

Pink skin is at risk!

How to Protect Your Horse From Sunburn

• The broad sweeping answer for preventing sunburn in summer is to limit exposure to UV light from the sun’s rays. This task is often much easier said than done.

Shade

• Keep your horse in the shade as much as possible. If your horse is always outdoors, position feeders in sheds or under trees (if safe) to encourage quality time out of the sun.

Dress your horse to block UV rays

• Fly masks, boots, and sheets are an easy way to help reduce UV exposure. Because these products must be airy, they won’t block all UV rays, but they can help.

• Fly masks with nose coverings are key for pink noses.

• Fly boots should be stiff enough to remain upright and cover the lower legs.

Some horses with pink skin around the eyes get “eyeliner” tattooed to help stop sun damage. 

Use sunscreen

• You can’t go wrong with a zinc oxide-based sunblock. These thick pastes last, and it’s easy to see when you need to reapply as the white coating fades.

• You can even use diaper cream, which is mostly zinc oxide. 

• Stick to sensitive skin formulas or baby formulas to minimize the ingredient list.

• You can use sunscreen sprays for a horse’s coat with or without fly sheets.

Food for thought

• Be mindful when you are clipping your horse. Freshly clipped horses of any color are more susceptible to sunburn.

• Use fly sheets with neck covers if your horse’s mane is roached or braided for shows. Those little gaps between braids and less hair spaces can burn.

• Don’t overlook the possibility of sun damage along your horse’s topline, especially for white horses, pintos, or paints. Don’t put anything on the saddle area as this heals.

Long-nosed fly masks are fantastic. If the nose area is getting goopy, spray it out with the jet setting of your hose nozzle.

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