Histologically, delayed burn blisters are sub-epidermal blisters with minimal inflammation. It has been shown that a discontinuity of the basement membrane may be the main anomaly, with a disturbed reassembly of the basement membrane components contributing to it. An enhanced fragility of the newly synthesized, ’immature’ dermo-epidermal junction could be responsible for this delayed blistering. It has been reported that the antigenic components of the normal dermo-epidermal junction appear sequentially during wound healing as they do in fetal life. They tend to heal spontaneously and can have a distinct tendency for recurrence over a period of weeks to months. They remain confined to the injured site not encroaching on the surrounding normal skin which can be an important pointer towards this possibility. Clinically these are seen in the form of tense vesicles or blisters, developing spontaneously after a prolonged interval of complete healing of the injured skin. ![]() Delayed blisters, observed weeks to months after initial healing in cases with second-degree thermal burns, on donor sites, and on recipient sites of split-thickness skin grafts have been known. In contrast, the phenomenon of delayed burn blisters has received very little attention in the literature. (×100)Īcute burn blisters are a well-known entity and a subject of intensive study. Periodic acid Schiff stain showing an irregular and discontinuous basement membrane. ![]() At this stage the injections were discontinued and the patient was kept under regular follow-up. There was a marked reduction in hypertrophic scar at the end of 2-5 months with significant flattening of the lesion and improved symptomatology. For the management of the hypertrophic scar, intralesional triamcinolone acetonide 40 mg/ml injections were started after the complete healing of the ulcer. The raw area healed completely over a course of 10 days. No oral antibiotic or any other medications were prescribed. The area was dressed with non-adherent, paraffin dressing. The patient was reassured and counselled regarding the condition. Based on the clinical and investigational outcomes, a diagnosis of delayed burn blister was kept. Immunoelectron microscopy could not be performed due to financial constraints. Direct immunofluorescence (DIF) for IgG, IgM, IgA and C3 were all negative. The periodic acid Schiff (PAS)-stained sections showed a poorly formed basement membrane. A histopathologic examination of the blister edge biopsy revealed a sub-epidermal blister, along with loss of dermal appendages, marked fibrosis, and presence of neutrophils. Nikolsky`s sign as well as Bulla spread sign were negative.Ĭlinical photograph showing hypertrophic scar with blister containing sero-sanguinous fluidīoth Grams-stained and Giemsa-stained smears from the blister fluid showed only neutrophils without any evidence of microorganisms or multinucleate giant cells. Overlying it was a blister filled with sero sanguinous fluid, surrounded by crusted erosion. 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. There was also no suggestion of dermatitis artefacta. The blisters were confined to the scar and healed over a few days with depigmentation. These blisters arose spontaneously without any predisposing factors in the form of trauma, contact with irritants, or local site infection. There was history of 5-6 similar episodes till the time of presentation to us. The first episode of blistering was a year after scar formation which healed over 1-2 weeks. ![]() The same healed over a 2 month period but left behind a hypertrophic scar. The patient had sustained a thermal burn with accidental spillage of boiling water, over his left forearm, 5 years ago. 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. Delayed post-burn blistering is an interesting and unusual phenomenon which has received little attention in the literature.
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