This child has fallen off his or her growth curve. This indicates an underlying disease process. The etiology of this child's anemia is most likely celiac disease or
inflammatory bowel disease.
References:
Zella GC & Isreal EJ. Chronic Diarrhea in Children. Pediatrics in Review 2012; 33: 207-218.
Overview on chronic diarrhea. Comprehensive differential diagnosis.
Hyams JS. Inflammatory Bowel Disease. Pediatrics in Review Vol. 26 No. 9 September 1, 2005, pp. 314–320.
An overview of IBD with a focus on differential diagnosis, presenting features as well as an overview of medications for IBD.
Iron Deficiency and Other Types of Anemia in Infants and Children. Am Fam Physician. 2016 Feb 15; 93(4):270-278.
http://www.aafp.org/afp/2016/0215/p270.html
Key recommendations for practice with flow diagrams capturing diagnosis based on age and MCV.