[Sepsis due to Pseudomona as a debut of a primary immunodeficiency in a child]

X-linked agammaglobulinemia is a primary humoral immunodeficiency. It is a recessive X-linked disorder characterized by low or absent circulating mature B cells, hypo/agammaglobulinemia and no humoral response to immunizations due to mutations along chromosome X. It is characterized by severe, recurrent and difficult treatment infections. It is diagnosed in the first 6 months of life in children; the only sign of alarm is the absent or decreased size of tonsils and lymph nodes, but it is not always present. The main cornerstones of treatment are immunoglobulin replacement therapy to maintain serum levels above 500-700 mg/dl and infection control; this allows these patients to do their day-to-day activities. We report a 2 year old boy with X-linked agammaglobulinemia, with no history of interest, who presented with P. aeruginosa sepsis. He had an excellent clinical improvement without further important infections after intravenous immunoglobulin replacement therapy.