Acute monomorphic papular eruption in the chest right after a day at the beach in July.
Case Discussion
Polymorphic light eruption is the most common photodermatosis. It presents in young adults as papular rash, vesicles or plaques 18-24 hours after light exposure usually in the spring/summer. Microscopically, it shows perivascular lymphohistiocytic infiltrate in superficial dermis. Papillary dermal edema, epidermal acanthosis, and spongiosis are also seen. There is variable increase in eosinophils and neutrophils.
Image Contributors
Morgan, S., Mete, O.
Cite
Morgan, S., Mete, O. Skin, Polymorphic light eruption. Digital Laboratory Medicine Library, Dept of Laboratory Medicine & Pathobiology, University of Toronto. Published
. Accessed December 17, 2025. https://dev.dlml.cflabs.ca/image/skin-polymorphic-light-eruption-lmp58920
