What should I check if my horse's photosensitivity is getting worse?
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Overview
If your horse’s photosensitivity seems to be getting worse, check whether there’s been more sun exposure, a change in turnout, or any new redness, swelling or skin damage. It could be something as simple as increased UV exposure, but ongoing or worsening photosensitivity can also be linked to irritation, plants, feed changes or an underlying health issue, so it’s worth keeping a close eye on it.
Things To Check
1. Check whether the problem is worse after turnout, during bright sunlight, or on areas with thin hair and pale skin.
2. Look closely for redness, swelling, crusting, scabs, peeling skin, sores or oozing.
3. Check the face, muzzle, ears, back and any white legs or white markings, as these areas are often more exposed.
4. Think about any recent feed, supplement or grazing changes, especially if they happened before the skin reaction worsened.
5. Check for contact with plants, mud, chemicals or newly treated pasture that might have irritated the skin.
6. Notice whether your horse is rubbing, head shaking, stamping or trying to avoid bright areas, as that can suggest discomfort.
7. Check whether the skin feels warm or painful to touch, without pressing on sore areas.
Common Causes
The most common cause is increased sun exposure on sensitive or lightly pigmented skin. Photosensitivity can also be made worse by rubbing, irritation from plants or chemicals, or a reaction to something in the horse’s environment.
Less commonly, it may be linked to feed changes, liver-related problems, or another underlying condition that’s making the skin react more strongly to sunlight.
What To Do
Keep a simple record of when the signs appear, which areas are affected and what has changed recently. This can help you spot patterns.
If possible, reduce strong sun exposure for the affected horse, especially during the brightest part of the day. Check turnout, shelter and any recent changes to pasture access.
Gently clean only as needed, and avoid harsh scrubbing or products that could make the skin more uncomfortable. If the area is sore, try to keep handling to a minimum.
It’s also sensible to review feed, supplements and grazing changes with care, especially if the skin problem started or worsened after a change.
When To Contact A Vet
Contact your vet if the photosensitivity is spreading, the skin looks badly damaged, your horse seems painful, or the problem keeps getting worse despite reducing sun exposure. It’s also sensible to get advice if you suspect a feed, plant or health-related cause.
Seek prompt veterinary help if you notice marked swelling, fever, lethargy, poor appetite or signs that suggest the horse is unwell as well as having skin changes.
Products That May Help
If your horse's skin is feeling more sensitive, a gentle washing routine can help support day-to-day coat and skin care without being too harsh.
Related Questions
How can I tell if my horse’s photosensitivity is linked to sunlight?
What areas should I check first on a horse with sensitive skin?
When should photosensitivity in horses be checked by a vet?
Atlas is here to support owners with practical, easy-to-understand guidance. It is not a substitute for professional veterinary advice. If you're concerned about your animal's health, symptoms worsen, or something doesn't feel right, contact your vet.