VPT 421: Veterinary Toxicology (2+0)

INTRODUCTION

• Photosensitization is a clinical condition in which skin (areas exposed to light and lacking significant protective hair, wool, or pigmentation) is hyper-reactive to sunlight due to the presence of photodynamic agents.
• Molecules of photosensitizing agents present in the skin are energized by light.
• When the molecules return to the less energized state, the released energy is transferred to receptor molecules that quickly initiate chemical reactions in various skin components.
• Tissue injury is thought to result from the production of reactive oxygen intermediates or from alterations in cell membrane permeability.
• Photosensitization can be difficult to differentiate clinically from actual sunburn.