Photosensitivity reactions can be classified into two main types:
Phototoxic reactions: These are non-immunologic responses that occur when a photosensitizing agent absorbs light and causes immediate damage to the skin cells. They are dose-related and resemble sunburn. Photoallergic reactions: Unlike phototoxic reactions, these are immune-mediated responses. They occur when the light-altered chemical structure of a compound is recognized as an antigen by the immune system, leading to delayed hypersensitivity reactions.
