Food protein induced enterocolitis syndrome (FPIES) is the most severe GI food hypersensitivity that is not IgE mediated. FPIES is thought to be caused by a delayed, cell mediated allergic pathway. This condition results in profuse, repetitive vomiting, diarrhea, acute dehydration, lethargy and weight loss. It can eventually lead to failure to thrive.
Upon challenge, an FPIES patient will typically begin with severe, repetitive vomiting 1-3 hours after ingestion; diarrhea, 2-10 hours after diarrhea; lethargy; pallor; low blood pressure; hypothermia; and abdominal distention. They will often show a spike in neutrophils, being highest around 6 hours after exposure; elevated platelets; metabolic acidosis; high methemoglobin; white blood cells in feces, including eosinophils; fecal blood, frank or occult; increased carbohydrates in stool; and elevated white blood cells in gastric juice. Vomiting is seen in 100% of episodes; lethargy in 85%; pallor in 67%; diarrhea in 24% and hypothermia in 24%.
Chronic symptoms from repeat ingestion of responsible food include intermitten, chronic vomiting; frequent, watery diarrhea, often with blood or mucus; lethargy; dehydration; abdominal distention; weight loss; and failure to thrive. Patients with chronic symptoms are often anemic; have low serum albumin; have elevated white blood cells, especially eosinophils; have metabolic acidosis, in which the body produces too much acid and the kidneys cannot remove it quickly enough; have methemoglobinemia, too much of a form of hemoglobin that binds oxygen poorly; intramural gas, gas within the wall of the bowel; and air fluid levels, a radiologic finding often associated with bowel obstruction.
About 75% of FPIES patients appear seriously ill. 15% are hypotensive enough to require hospitalization.
FPIES almost exclusively begins in infancy. Age of onset is typically between 1 and 3 months of age, but can be as late as 12 months. It is slightly more common in males, with male cases accounting for 52-60% of cases. Symptoms generally begin within 1-4 weeks of introducing cow’s milk or soy. Sometimes these substances are tolerated, but FPIES to a solid food shows, with rice being the most common offending solid. Egg is extremely rare as a cause of FPIES reactions.
FPIES has been well studied. About 30% of FPIES patients go on to develop atopic conditions, with 25-65% getting atopic dermatitis; 3-20%, asthma; and 20%, allergic rhinitis. 40-80% of patients have a family history of atopic disease and 20% have a family history of food allergies.
A history of FPIES to one grain gives a 50% chance of reaction to other grains. In cases of solid food FPIES, 80% react to more than one food. 65% were previously diagnosed with FPIES to cow’s milk or soy. 35% were breastfed.
Patients usually improve significantly within 3-10 days of beginning casein hydrolysate-based formula with or without IV fluids. In infants who have generic GI symptoms early on, switching to a hypoallergenic formula can prevent fullblown FPIES.
Leonard, Stephanie, Nowak-Wegrzyn, Anna. Food protein induced enterocolitis syndrome: an update on natural history and review of management. Ann Allergy Asthma Immunol. 2011; 107:95-101.
Caubet, Jean Christoph, et al. Clinical features and resolution of food protein induced enterocolitis syndrome : 10-year experience. J Allergy Clin Immunol. 2014; 134(2): 382-389.