ICD-10 Code K52.21 – Food protein-induced enterocolitis syndrome (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K52.21 – Food protein-induced enterocolitis syndrome
What it is
K52.21 identifies food protein-induced enterocolitis syndrome, a non-IgE-mediated food allergy that affects the gastrointestinal tract. It is used when a specific food triggers delayed intestinal inflammation and vomiting or diarrhea.
Clinical signs
Typical features include repetitive vomiting, diarrhea, lethargy, pallor, and dehydration after eating the trigger food. Clinical features vary; refer to documentation.
When to use this code
Use K52.21 when the record documents FPIES or food protein-induced enterocolitis syndrome as the diagnosis. It may also apply when a clinician links recurrent delayed GI reactions to a specific food and confirms the syndrome. Check documentation if the trigger food is not clearly identified.
Do not use for
Do not use this code for simple food intolerance, infectious gastroenteritis, or unspecified allergic reactions without enterocolitis syndrome. If the note only says “food allergy,” check documentation.
Coding tip
Code the syndrome only when the provider documents FPIES or clearly describes the condition; do not infer it from nonspecific vomiting alone.