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FPIES is part of a family of gastrointestinal conditions that are caused by non-IgE allergic reactions to food proteins. FPIES (food protein induced enterocolitis syndrome) affects the whole gastrointestinal tract. FPE (food protein enteropathy) affects only the small intestine. FPIAP (food protein induced proctocolitis) affects only the distal colon. This article will focus on FPIES. 

FPIES can be divided into acute and chronic types. Chronic FPIES is usually diagnosed in younger infants and is caused by an immune reaction to the proteins in either cow’s milk or soy formulas. Acute FPIES usually occurs in response to the introduction of solid food around 4-7 months. The most common trigger foods for acute FPIES are rice, oats, sweet potato, squash, banana, avocado, peas, green beans, chicken, turkey, and eggs. Though FPIES is most often diagnosed in infants, it has been observed fetally and in adults. 

Symptoms of FPIESA woman comforts an ailing toddler.

Symptoms of Chronic FPIES

  1. Chronic watery diarrhea (blood and/or mucous may be present)
  2. Occasional vomiting
  3. Bloated abdomen
  4. Poor weight gain
  5. Infants with severe chronic FPIES may also be dehydrated or have metabolic disturbances caused by diarrhea and vomiting.
  6. Symptoms typically resolve within several days of removing the trigger food(s). When the food is reintroduced, acute FPIES symptoms may occur. 

Symptoms of Acute FPIES

  1. Repetitive vomiting 1-4 hours after ingesting trigger food
  2. Diarrhea may occur later
  3. Lethargy
  4. Pale skin
  5. Hemodynamic instability and shock may occur

Diagnosis of FPIES

At present there are no definitive tests available for FPIES, instead a diagnosis relies on clinical evaluation by a doctor. Similar symptoms can be caused by other allergic conditions, infectious disease, and other gastrointestinal conditions so a full work-up may be done depending on the individual case. 

An oral food challenge is usually part of the diagnostic procedure. This is considered a high risk procedure and should always be done in a medical setting. New research states that an oral food challenge may not be necessary for diagnosing acute FPIES provided more than one episode has been observed. However, an oral food challenge is considered necessary for diagnosing chronic FPIES and for diagnosing acute FPIES if there is any uncertainty. 

Treatment of FPIES

The most important part of FPIES treatment is the removal of trigger foods. Once symptoms have stabilized other considerations include ensuring good nutrition, healing the gut, and immune and inflammatory support. Most children will outgrow FPIES by 3-5 years of age, though it may continue longer. 

Removing Trigger Foods

For infants with chronic FPIES in response to cow’s milk formula, replacing cow’s milk formula with extensively hydrolyzed formula is advised. Approximately 10-20% of infants will still react to extensively hydrolyzed formula and will require an amino acid formula. Partially hydrolyzed formulas are not advised. Soy milk formulas are an alternative if they are tolerated, but 40-60% of infants with cow’s milk FPIES will also react to soy milk formula. Goat and sheep milk formula aren’t recommended because the proteins are similar to cow milk and will likely cross react

FPIES is very rare in exclusively breastfed infants, but it does occur. In these cases, the mother’s diet needs to be modified in order to avoid the allergenic foods. If this isn’t possible, the infant can be switched to one of the formulas mentioned above.

For infants with acute FPIES, the offending food is removed and nutritionally similar replacements are found. It is usually not necessary to restrict foods with “may contain traces of” on the label. It is not usually necessary for breastfeeding mothers to restrict their diets unless infants are reacting to breast milk as in the rare cases described above. Additionally, some children with FPIES may be able to tolerate the baked version of the food but not the raw version. A doctor or nutritionist can provide individualized recommendations. 

Ensure Good Nutrition

FPIES often results in malabsorption so nutrient supplementation may be necessary. The most common micronutrient deficiencies are vitamin D, calcium, zinc, and selenium. Anemia may also be present. Depending on the child, a well rounded multivitamin with fish oil may be enough to boost nutrient stores, but more targeted supplementation may be required.

Weaning can be a stressful time when infants exhibit reactions to certain foods. Recommended weaning foods tend to change over the years as new data emerges. Currently, it is recommended that first foods for infants with FPIES be low risk for allergies. Example low risk foods are blueberries, broccoli, cauliflower, bone marrow, etc. The most common trigger foods for FPIES are: rice, oats, sweet potato, green beans, peas, squash, banana, avocado, chicken, turkey, and eggs. Some doctors recommend that foods be introduced one at a time with spaces of several weeks between new foods. 

Heal Gut

FPIES can cause damage to the gastrointestinal tract. The good news is that infants and kids often heal quickly without any intervention once the offending food is removed. However, if some symptoms are lingering, taking some steps to heal the gut may be wise. I recently wrote an article about how to heal the gut for kids where I go into greater detail about diet, lifestyle, and supplements. 

Five Main Steps to Heal the Gut

  1. Reduce inflammation by choosing anti-inflammatory foods.
  2. Reduce stress when eating by practicing mindful eating (or mindful nursing or bottle feeding).
  3. Soothe and repair tissues using vitamins, minerals, amino acids, and herbs.
  4. Strengthen digestion by using bitter foods and herbs and/or gentle walking or leg cycling after meals.
  5. Rebalance the gut microbiome using probiotics and fermented foods. 

Immune and Inflammatory Support

Though this is still an area of ongoing research, emerging data shows that immune dysregulation and inflammation play a role in FPIES. A diet and lifestyle that support healthy inflammatory balance are good for the whole family and may be especially helpful for children with FPIES. 

Immunomodulating herbs and probiotics may help rebalance the immune system and lead to sooner resolution of FPIES. However, this is purely speculative right now because the research is still sparse.

Emergency Management Plan

Doctors will often provide parents with written instructions for how to manage emergencies in the event that a severe allergic reaction occurs. This includes instructions about how to manage food allergen exposure at home and when to go to the emergency room. These instructions can also be given to emergency room physicians who may not be familiar with FPIES. 


FPIES (food protein induced enterocolitis syndrome) is a serious allergic reaction to certain foods. FPIES usually develops in infancy and resolves around 3-5 years of age. 

Avoidance of triggering foods, ensuring good nutrition, healing the gut, balancing the immune system and maintaining a good inflammatory balance are keys to treatment.  



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Verduci, E., Salvatore, S., Bresesti, I., Di Profio, E., Pendezza, E., Bosetti, A., Agosti, M., Zuccotti, G. V., & D’Auria, E. (2021). Semi-Elemental and Elemental Formulas for Enteral Nutrition in Infants and Children with Medical Complexity-Thinking about Cow’s Milk Allergy and Beyond. Nutrients, 13(12), 4230.

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Dr. Green Mom

Dr. Mayer is a naturopathic medical doctor and an expert in nutrition and wellness as it relates to pediatrics and families. Her passion for prevention of disease as cure fueled her desire to immerse herself into specializing in adult onset chronic conditions, as well as childhood chronic illness.

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