Bullous Diabeticorum

A 25-year-old male patient known for poorly controlled type 1 diabetes mellitus, presented with 1-day history of acute onset asymptomatic blister on right leg.It was not preceded by trauma, an insect bite or application of any products.There was no recent introduction of new medications and he had no history of fever or constitutional symptoms.He denied any similar previous eruptions.Skin examination revealed tense bullae of approximately 8 15 cm on his right lateral leg with mild rim of erythema [Fig.1].There were no oedema, mucosal involvement or lymphadenopathy and Nikolsky sign was negative.Differential diagnoses included bullous diabeticorum, exaggerated bullous insect bite reaction, bullous fixed drug reaction and immunobullous disorders.His glycated haemoglobin ranged between 14-15%.Skin biopsy revealed cell poor subcorneal blister with no inflammatory or acantholytic cells [Fig.2].Immunofluorescence for IgA, IgG, IgM and C3 were negative from perilesional skin.Fluid swab culture grew light growth of staphylococcus argenteus.Subsequently, he was diagnosed with bullous diabeticorum and managed with optimal wound care and prophylactic systemic antibiotic to prevent bacterial superinfection given large area of involvement.He healed completely in 10 weeks with post inflammatory hyperpigmentation.