A Rare Presentation of Isolated IgM Deficiency in a 28-Year-Old Male: A Case Report.

Immunoglobulin M (IgM) plays a regulatory role in subsequent immune response development, thereby accelerating the production of immunoglobulin G (IgG) with high affinity. Selective IgM deficiency (SIGMD) is a rare immune disorder that has been reported in association with serious infections, such as bacteremia. Patients commonly present with infections, atopy, septicemia, splenomegaly, neoplasia, and other autoimmune disorders. Treatment modalities and recommendations range from careful monitoring to vaccinations, aggressive management of respiratory infections, preventive and therapeutic antibiotics, and intravenous immunoglobulin (IVIG). There is insufficient information to generalize patients' prognosis with selective IgM deficiency due to the small number of patients and lack of prospective studies. We hereby present the case of a 28-year-old male with multiple recurrent boils, cellulitis, and osteomyelitis who has been diagnosed with selective IgM deficiency and is being treated with IVIG. This case report highlights the diagnostic evaluation and therapeutic care of patients with SIGMD and the need for follow-up.