A320 cow milk protein allergy - the great masquerader

Cow milk protein allergy is a very common disease, with a prevalence of 2 to 7.5% in the pediatric population. The diagnosis is often made clinically and appears early, usually during the first few months of life. Common clinical presentations include: reflux, atopic dermatitis, failure to thrive, chronic diarrhea, as well as rectal bleeding or enterocolitis. Severe, life-threatening, presentations are very rare.The 2 reported cases show that cow milk protein allergy may have a very early and severe presentation and can even mimic some surgical diagnoses. Case n°1 An 8-day-old formula-fed male infant with no significant personal or family history of atopic disease was transferred to our hospital with bilious vomiting and abundant hematochezia. Small intestinal volvulus was suspected, but laparotomy was normal. In the face of persistent rectal bleeding and severe anemia (Hgb 73g/l), rectal biopsy and upper endoscopy were performed and showed mild colitis and severe gastritis with mucosal desquamation. Biopsies revealed an important infiltration of eosinophilic cells (>100/HPF in the stomach and severe eosinophilic proctitis). Peripheral eosinophil count was initially normal, but hypereosinophilia appeared at day 3 of admission (maximum 2600 106/L at 16 daysof life). After 8 days of bowel rest with total parenteral nutrition, progressive refeeding was initiated, with an amino acid based formula and was well tolerated. Case n°2 A newborn female infant was transferred to our hospital for suspected intestinal obstruction. She was breastfed and had a brother with cow’s milk protein allergy. She presented with bilious emesis and mild rectal bleeding a few hours after birth. Abdominal X-ray showed small bowel dilatation. Ultrasound and small bowel opacification did not demonstrate volvulus or malrotation. Enteral feeding was started with standard formula 48 hours after admission.Three days later, she suddenly deteriorated and developed acute diarrhea with hypernatremic dehydration (Na: 165mmol/l) and metabolic acidosis (pH: 7.145, bicarbonate level: 11mmol/l). Feedings were stopped but 24 hours later she once again developed rectal bleeding. A severe colitis was seen on endoscopy and biopsies showed eosinophilic infiltration of the mucosae with >70 eosinophils/HPF. Rectal bleeding stopped 3 days after she was made NPO. Peripheral eosinophilia (max 3000 106/L) appeared at day 6 of life. She responded well to an amino acid based formula and peripheral hypereosinophilia resolved. The above cases show that cow milk protein allergy can have an acute and severe presentation and can even mimic surgical pathologies in early life. Atypical clinical manifestations of cow milk protein allergy need to be recognized by pediatricians and primary care physicians in order to improve the management of these patients. Ste Justine Fundation