Selective immunoglobulin M deficiency presenting with recurrent impetigo: a case report and review of the literature.

Selective immunoglobulin M (IgM) deficiency is a rare disorder defined by a decreased serum level of IgM and normal levels of other immunoglobulin classes. The disease has not been well described and the cause remains unknown. Patients with IgM deficiency may present with a wide spectrum of clinical manifestations, from asymptomatic to life-threatening infections, including recurrent respiratory and gastrointestinal infections, allergy and autoimmunity. Here, we report a 6.5-year-old otherwise healthy boy with selective IgM deficiency who presented with multiple recurrent impetigo. We reviewed the published data regarding selective deficiency of IgM.