Photosensitisation (Light Dermatitis)

Veterinary care required

This condition belongs in veterinary diagnosis and treatment. Compounds are at most supportive.

Priority · vet & management

It is important to have a vet clarify whether a primary (plant) cause or a secondary, liver-associated form is present — because with the latter, liver diagnostics (blood values) determine prognosis and approach. Immediate measures are consistent sun protection (shade, covering, time off pasture) and removing suspect plants; skin treatment and liver work-up belong in veterinary hands.

Possible causes

• · primary: photosensitisers from plants (e.g. St John's wort, buckwheat)
• · secondary (hepatogenic): liver damage with phylloerythrin build-up (e.g. after poisonous plants such as ragwort)
• · intense sun exposure on unpigmented skin
• · certain medicines as rare triggers

Supportive compounds · supplementary feed, not medication

Prevention

Keep photosensitising poisonous plants away from pasture and hay and protect unpigmented horses during the intense sun phase (shade, rugs, adjust turnout times).

Equiterna's take

Equiterna emphasises the central distinction between primary and secondary: white skin that becomes sore in the sun can be a skin problem — or a warning sign of the liver. The liver-associated form makes veterinary diagnostics indispensable.