Gravel-Associated Bullous Foreign Body Reaction in the Setting of Systemic Lupus Erythematosus on Immunosuppression

Summary: A 42-year-old woman with a past medical history of systemic lupus erythematosus on Benlysta presented to the dermatology clinic in January 2021 due to a non-healing traumatic scar from a bike accident that occurred on the left knee at the end of October 2020. The patient noted that she deeply scraped and cut her left knee on gravel/coal during the bike accident. At this initial visit, her lesion on the left knee appeared to be blister-like with clear pink fluid draining from the site. The lesion did not heal and is tender to touch. After the incident, the patient visited urgent care that day where she had the area scrubbed. She then presented to dermatology clinic where a 6mm punch biopsy was taken revealing an ulcerated cicatrix with small focus of foreign body reaction. The patient was started on a series of Intralesional Triamcinolone injections at 10mg/ml for a total dosage of 0.6mls. She was instructed to follow-up in 4-6 weeks. At the follow-up visit, her bullous foreign body reaction was persistent despite treatment with Intralesional Triamcinolone injections. A few months later, the patient noted persistent itchiness and paresthesia at the site. She was recommended to follow-up with Plastic Surgery for revision and excision of the scar. Overall, this case presents a persistent, unique foreign body reaction likely due to gravel and resistant to Intralesional Triamcinolone treatment in an immunosuppressed patient.