History: 6313mr Onset over 6 weeks of a blistering eruption in this distribution with associated fever. She had a diagnosis of Polymyalgia rheumatica 3 months ago and was on oral steroids. I think she has Pemphigus erythematosus with a differential of drug induced blistering , toxic epidermal necrolysis or Staph scalded skin syndrome.

Description: Lichenoid dermatitis

Comments: The biopsy shows prominent impetiginisation with numerous bacteria and some neutrophils within the cornified layer. The underlying epidermis shows a lichenoid reaction with basal and suprabasal apoptotic keratinocytes and a mild superficial dermal perivascular lymphohistiocytic infiltrate. The features are those of an impetiginised lichenoid dermatitis. The lichenoid reaction appears interface obscuring and possibilities would include a drug reaction, subacute cutaneous lupus, chronic EM and a paraneoplastic eruption. Immunofluorescence is negative. This proved to be a drug induced subacute lupus erythematosus with secondary infection