Abstract

Polymorphous light eruption (PMLE) is a common photodermatosis characterized by a skin eruption following sun exposure.  As its name suggests, its clinical appearance is variable.  Histologically, it is traditionally characterized by papillary dermal edema and a dense perivascular lymphocytic infiltrate; however, the histologic features may be as polymorphous as the clinical findings.  Epidermal to dermal separation has been known to occur and has been thought to be secondary to edema rather than lichenoid or vacuolar damage.  However, we present two patients with PMLE who exhibited interface dermatitis without evidence of connective tissue disease.  PMLE with interface changes has not been well documented in the literature.  One of our cases demonstrated vacuolar interface dermatitis and the other showed a lichenoid interface dermatitis with papillary dermal edema and a superficial perivascular lymphocytic infiltrate.  Interface dermatitis in PMLE may represent an underrecognized feature or histopathological variant.  Further studies are warranted to explore the pathogenesis and clinical significance of PMLE with interface change.