Introduction

Polymorphic light eruption is a photodermatosis characterised by an erythematous, papular and vesicular rash developing in areas exposed to UV radiation. Lichen planus in the eruptive variant presents with diffuse polygon-shaped papules accompanied by pruritus. Necrobiosis lipoidica manifests as yellow-brown atrophic plaques with central telangiectasias, typically located on the lower legs.

Objective

Presentation of a case of atypical coexistence of polymorphous light eruption, eruptive lichen planus, and necrobiosis lipoidica.

Case report

A 59-year-old woman with a history of necrobiosis lipoidica involving the skin of both lower extremities was admitted to the Department of Dermatology for the diagnosis work-up of skin lesions that appeared 2 weeks earlier. Confluent erythematous and papular lesions were observed on the skin of the neck, chest, shoulders, and back. Additionally, diffuse pruritic papules were noted within the upper and lower extremities and in the sacral region. The histopathological features of a skin sample taken from the back and forearm were consistent with polymorphous light eruption and lichen planus, respectively. Clobetasol and antihistamines were used, leading to an improvement in skin condition.

Conclusions

Simultaneous occurrence of the three dermatoses mentioned above is an uncommon phenomenon, and may be diagnostically challenging. Consequently, effective diagnostic management should incorporate histopathological examination in correlation with the clinical presentation and comprehensive anamnesis.