Immunodeficiency states in children can arise from congenital or acquired causes. Primary immunodeficiency states can be a result of a T cell, B cell, phagocytic or complement defect. Children with a T cell defect such as in severe combined immunodeficiency often present in the newborn period with disseminated BCG infection following BCG vaccination, recurrent respiratory or gastrointestinal infections and significant failure to thrive. In contrast, children with humoral immunodeficiency such as in X-linked agammaglobulinemia, present in late infancy as maternal IgG from placental transfer helps the baby for the first few months of life following which they get repeated respiratory and gastrointestinal infections. Children with phagocytic defects as in chronic granulomatous disease, typically present with skin abscesses and deep seated infections such as liver abscess. Complement defects can present with recurrent meningococcal infections. Management should include prompt and appropriate antibiotics to treat the current infection, prophylactic antibiotics to prevent further infections and genetic counseling. Stem cell transplantation offers the sole chance of cure in most primary immunodeficiency disorders.

Neutropenia post cancer chemotherapy and HIV/AIDS are the two acquired immunodeficiency conditions seen in children. Neutropenic patients are at risk from organisms in their own mouth, gut and skin. Strict personal hygiene, clean water and the use of only cooked food are of utmost importance in the care of neutropenic children. The use of alcohol hand rubs and dedicated equipments, such as a stethoscope help prevent cross infection. There is no role for prophylactic antibiotics in neutropenic children. If they spike a fever more than 100oF, blood cultures are drawn and broad spectrum antibiotics like cefepime or cefoperazone sulbactam are started empirically. Growth factors such as GCSF and GM-CSF help reduce the period of neutropenia and are started simultaneously. Immune reconstitution is rapid in children with HIV after starting appropriate retroviral therapy.