K52.21 vs T78.41XA
K52.21 (Food protein-induced enterocolitis syndrome) compared with T78.41XA (Arthus phenomenon, initial encounter), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. T78.41XA carries an Excludes1 note covering K52.21: “food protein-induced enterocolitis syndrome (K52.21)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| K52.21Food protein-induced enterocolitis syndrome | T78.41XAArthus phenomenon, initial encounter | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | K00-K95 — Diseases of the Digestive System (K00-K95) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Food protein-induced enterocolitis syndrome is a billable ICD-10-CM diagnosis code (K52.21). | Arthus phenomenon, initial encounter is a billable ICD-10-CM diagnosis code (T78.41A). |
| 7th character | — | The appropriate 7th character is to be added to each code from category T78 |
| Includes | noninfective inflammatory bowel disease FPIES | Arthus reaction |
| Use additional code | code for hypovolemic shock, if present (R57.1) code to identify type of food allergy (Z91.01-, Z91.02-) | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources