Dr. MacArthur joined the Department of Otolaryngology-Head and Neck Surgery at OHSU in 2002. She came from Children's Hospital of Orange County (CHOC) and the University of California, Irvine in Orange, California where she was in practice from 1991-2002. Dr. MacArthur completed a pediatric otolaryngology fellowship at Harvard Medical School/Boston Children's Hospital, in Boston, Massachusetts before beginning her practice in 1991. She completed her training in otolaryngology-head and neck surgery at the University of California, Davis. She received her medical degree at UCLA and undergraduate degree in chemistry at Occidental College in Los Angeles, CA.

Dr. MacArthur has a strong clinical interest in the treatment of hemangiomas and vascular birthmarks. She co-founded the hemangioma and vascular birthmarks team at OHSU in 2003. This team provides multidisciplinary care to children and adults with complex hemangiomas and vascular birthmarks, offering the most up-to-date treatment options, both medical and surgical and via interventional radiology. 

She is an active mentor to students and residents. She is chief of the Division of Pediatric Otolaryngology here at OHSU and is starting a fellowship program to train future leaders in this field. She has over 40 peer-reviewed publications, is active in editorial review activities for several medical journals and granting agencies. She serves on numerous committees to support the OHSU institution in Professionalism, faculty council and as co-chair of the Committee on Committees. She also serves on the American Society of Pediatric Otolaryngology Task Forces on fellowship, vascular birthmarks, research, voice, and recurrent respiratory papillomas. 

In addition, from 2005-2014, Dr. MacArthur was funded through the NIH as a co-investigator with Dennis Trune, Ph.D. to study the inner ear impact of chronic middle ear inflammation (mouse model), steroid responsive mechanisms in the ear (mouse model), and the genetic susceptibility to otitis media –candidate genes. She also received a grant from the National Organization for Hearing Research (NOHR) in 2011 to study the genetic variation in the immune system to otitis media. She collaborates with an international group interested in the genetics of chronic otitis media including research teams from the UK, Finland, Pittsburgh and Australia on this effort. She has recently received a grant from the  "Action on Hearing Loss" Foundation in 2015 to continue the genetic investigation of chronic otitis media.