Delayed Burn Blister

Delayed post‐burn blistering is an interesting and unusual phenomenon which has received little attention in the literature.[1,2] We herein report a case of a 20‐year‐old man who presented to the dermatology outpatient department with complaints of recurrent, apparently spontaneous blistering, occurring over a post‐ burn scar. The patient had sustained a thermal burn with accidental spillage of boiling water, over his left forearm, 5 years ago. The same healed over a 2 month period but left behind a hypertrophic scar. The first episode of blistering was a year after scar formation which healed over 1‐2 weeks. There was history of 5‐6 similar episodes till the time of presentation to us. These blisters arose spontaneously without any predisposing factors in the form of trauma, contact with irritants, or local site infection. The blisters were confined to the scar and healed over a few days with depigmentation. There was also no suggestion of dermatitis artefacta. On examination, there was a hypertrophic scar with well‐defined irregular margins, measuring approximately 20 × 6 cm, over the dorsal aspect of left forearm, extending to the flexor aspect as well. Overlying it was a blister filled with sero sanguinous fluid, surrounded by crusted erosion [Figure 1]. Nikolsky`s sign as well as Bulla spread sign were negative.