Transient hypogammaglobulinemia of infancy presenting as Staphylococcus aureus sepsis with deep neck infection.

Transient hypogammaglobulinemia of infancy (THI) is characterized by a prolongation and accentuation of the physiologic hypogammaglobulinemia normally occurring during the first 3 to 6 months of life and recovers spontaneously between 18 and 36 months of age. Infants with THI may remain asymptomatic or develop recurrent sinopulmonary infections, but severe or life-threatening infections are rare. We report a case of THI in a previously healthy 1-year-old girl with Staphylococcus aureus sepsis who subsequently developed deep neck infection confirmed by magnetic resonance imaging. Intravenous oxacillin was administered for 21 days and she recovered completely. Immunologic studies were normal except for decreased immunoglobulin G levels. Under the impression of hypogammaglobulinemia with severe infection she received regular intravenous immunoglobulins (IVIG) replacement therapy every 4 weeks. One year later, the immunoglobulin concentrations had returned to the normal range even though IVIG had been discontinued for 4 months. This case report highlights the possibility of severe infection in THI, a disease which usually has a benign clinical course. As the diagnosis of THI can only be made with certainty in retrospect, long-term follow-up of clinical and immune system status is necessary.