What Causes Horse Photosensitivity?

A common cause of hepatogenous photosensitivity is poisoning by grazing plants toxic to the liver or ingesting blue-green algae (cyanobacteria) or fungal toxins. The signs associated with photosensitivity are similar regardless of the cause.

What does photosensitivity look like in horses?

The signs associated with photosensitivity are similar regardless of the cause. Photosensitive animals are hypersensitive when exposed to sunlight and squirm in apparent discomfort. They scratch or rub lightly pigmented, exposed areas of skin such as the ears, eyelids, or muzzle.

How can horses prevent photosensitivity?

Sunburn and Photosensitivity in Horses

1. Keep horses stalled during the hours of most intense sun, and avoid turning horses out without access to shade.
2. Use a child-safe human sunblock preparation on areas that are likely to burn.
3. Reapply sunblock regularly.

Can horses be allergic to sun?

Sun-related Allergies True allergy, or hypersensitivity, to the sun is rare in horses. More common is “photosensitivity,” sun-related skin injury that’s triggered by chemical imbalances in the body. Forage plants are one possible culprit in the process but certain drugs or underlying liver disease may also be factors.

Do buttercups cause photosensitivity?

For example, photosensitive agents are present in St John’s Wort and buttercups (which can also be toxic to horses). A horse may also suffer from photosensitisation, secondary to liver failure. Affected horses will scratch or rub their skin when exposed to sunlight and may develop skin lesions including blisters.

Why does my horse have little bumps?

The most common reason that horses develop many small bumps on their skin is allergic hives (urticaria), but there are other causes that should also be considered. If the bumps appeared very suddenly and are distributed all over the body, it is likely true hives.

How do you treat pastern dermatitis in horses?

How do I treat pastern dermatitis?

1. Keep lower limbs dry.
2. Clip hair (Usually required in horses with feathering) and clean the affected areas.
3. Soak the affected limbs for 10 minutes with water.
4. Remove all scabs with a soft cloth, but DO NOT cause bleeding as this will lead to further scab formation.

What causes horse uveitis?

By far the most common type of uveitis in Germany and neighboring countries is classical equine recurrent uveitis (ERU), which is caused by chronic intraocular leptospiral infection and is the main cause of infectious uveitis in horses.

Is St John’s wort poisonous to horses?

Despite its sunny yellow flowers, St John’s Wort can make your horse very sick.

What is highly toxic to horses?

Weeds: Onions/garlic, ground ivy, milkweed, bracken fern, cocklebur, horsetail, white snakeroot, St. Johns wort, star-of-Bethlehem, sorghum/sudangrass, yellow sweet clover, blue-green algae, bouncing bet, larkspur, mayapple, skunk cabbage. Trees: Black locust, oak (green acorns), horse chestnut, boxwood, holly.

What plants can cause liver damage in horses?

Plants Toxic to Horses

• Alsike Clover.
• White and Red Clover.
• Tall Fescue.
• Buttercup Species.
• Pokeweed.
• Nightshade Species.
• Horsenettle.
• Poison Hemlock.

Are marigolds poisonous to horses?

Extreme exposure to, along with consumption of this plant is generally fatal. Marsh marigold poisoning in horses, a member of the buttercup family, is toxic to horses and humans when any portion of the mature plant is ingested.