Panniculitis associated with α1-antitrypsin deficiency (AATD) is well documented but rare. We report the first case, to our knowledge, of successful induction of clinical remission of AATD-related panniculitis following a single 120-mg/kg dose administration of plasma-purified α1-antitrypsin (AAT). A 23-year-old man with known PiZZ AATD presented to the hospital with a diffusely swollen and tender right upper limb. This was associated with subcutaneous induration, and a discrepancy of 5 cm in upper limb circumference at the mid arm was noted. There was no convincing precipitant for cellulitis or an infectious cause, and inflammatory markers were raised, with a C-reactive protein (CRP) level of 93.9 mg/L and erythrocyte sedimentation rate (ESR) of 71 mm/h. Doppler ultrasonography ruled out DVT. No antimicrobials or antiinflammatory medications were administered during or prior to admission. Biopsy specimens of the right upper limb revealed extensive panniculitis with neutrophils, foamy macrophages, and fat necrosis. A diagnosis of AATD-associated panniculitis was made. Following this, a single IV dose of 120 mg/kg of plasma-purified AAT was administered. By day 7 post AAT infusion, CRP level had normalized to 4.6 mg/L and ESR had dropped to 22 mm/h. Limb circumference discrepancy on day 7 was 1 cm. There was no tenderness to palpation or induration, and a clinical remission of panniculitis was observed. We report the first case, to our knowledge, of clinical remission following a single treatment with IV AAT at a dose of 120 mg/kg. This opens avenues to more timely and effective treatment of the more severe presentations of AAT-associated panniculitis.