PAINFUL SKIN LESIONS AFTER STARTING SUBCUTANEOUS IMMUNOGLOBULIN REPLACEMENT

Abstract

<h3>Introduction</h3> 17-year-old female with history of Behcet's, Sweet's syndrome, Chilblain lupus, inflammatory arthritis and ileitis complains of painful skin lesions of the extremities after initiation of subcutaneous immunoglobulin (SCIg) replacement (Cutaquig). <h3>Case Description</h3> Patient is on multiple immunosuppressants including ustekinumab, canakinumab, and leflunomide managed by Rheumatology. She has received intermittent IVIg at ∼1 g/kg (anti-inflammatory dosing) for joint pain and skin lesions. Due to post-IVIg headaches, SCIg was opted and the patient was started on Cutaquig 15 g weekly. On the 2nd - 3rd Cutaquig infusions, painful red/purplish lesions appeared on fingers and toes bilaterally, which worsened weekly with the infusions. Skin biopsy was considered, but the lesions crusted and resolved over a few weeks shortly after Cutaquig was stopped. Allergy and Immunology (A/I) has been involved in the patient's care for concern for hypogammaglobulinemia with lowest IgG at 469 mg/dL. Past immune evaluation showed normal IgG and appropriate response to Pneumovax two years ago. Genetic testing has been unremarkable so far. Recent evaluation revealed persistently low IgG and gradually down trending IgA at 623 mg/dL and 45 mg/dL, respectively. Additionally, the patient also had a few ear infections; thus, A/I currently trialing Cuvitru at IgG replacement dosing (∼500 mg/kg). <h3>Discussion</h3> Systemic reaction to SCIg infusions are rare and thus well tolerated by patients. In contrast, local reactions with swelling, pain, and bruising on SCIg infusion sites have been well reported. To our knowledge, systemic dermatological adverse reactions due to SCIg have not been reported in the past.