The photoallergic reaction involves two main steps: sensitization and elicitation. During the sensitization phase, a person is exposed to a photoallergen, which undergoes a chemical transformation upon exposure to UV light. This new compound binds to skin proteins, forming an antigen that triggers the immune response. Upon subsequent exposure to the same photoallergen and light, the elicitation phase occurs, where the immune system attacks the antigen, leading to an inflammatory reaction such as a rash or dermatitis.
