We encountered the case of an infant aged 5 months with autoimmune neutropenia (AIN) who presented with a parotid abscess caused by methicillin-resistant Staphylococcus aureus (MRSA). The infant improved early with puncture drainage of the external ear canal and antibacterial treatment with vancomycin (VCM). However, it was difficult to reach the proper dosage of VCM.
AIN is one of the chronic neutropenias of infancy and early childhood. It is primarily characterized by increased destruction of neutrophils by antineutrophil antibodies. It has been estimated to occur at a frequency of 1 in 100,000, but the number of cases diagnosed as having this condition appears to be increasing with the recent progress in techniques for measurement of antineutrophil antibodies. The infants present with recurrent mild bacterial infections, but the condition becomes less severe with an increase in the neutrophil count in almost every case by the age of five.
