Less common reaction resembling allergic contact dermatitis with delayed onset (24–72 h); form of delayed type hypersensitivity reaction due to allergen either taken systemically or applied topically
Prior exposure to allergen needed, and once sensitized any form of exposure may cause eruption; may see cross-reactivity unlike phototoxic eruptions
Presents with pruritus in sun-exposed areas with erythematous patches and papules, ± bullae; chronic exposure may cause lichenification
