T78.4 ICD-10-CM Code: Other and unspecified allergy
A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.
Official description
T78.4Other and unspecified allergy
ICD-10-CM diagnosis code · United States clinical modification
Where T78.4 sits
- 1
Chapter 19
Injury, poisoning and certain other consequences of external causes (S00-T88)
- 2
Section
Other and unspecified effects of external causes (T66-T78)
- 3
Category T78
Adverse effects, not elsewhere classified
- 4
Code T78.4
Other and unspecified allergy
Codes under T78.4
T78.4 is a non-billable category. Choose the child code that best matches the documented diagnosis.
Notes for this code
Inclusion terms
No inclusion terms are listed for T78.4.
Code first
No “code first” instruction is listed for T78.4.
Use additional code
No “use additional code” instruction is listed for T78.4.
Excludes1
Conditions that should not be reported together with this code.
- specified types of allergic reaction such as:
- allergic diarrhea (K52.29)
- allergic gastroenteritis and colitis (K52.29)
- dermatitis (L23-L25, L27.-)
- food protein-induced enterocolitis syndrome (K52.21)
- food protein-induced enteropathy (K52.22)
- hay fever (J30.1)
Excludes2
Conditions not included here that may be reported separately when present.
No Excludes2 note is listed for T78.4.
Source and release
- Data release
- U.S. ICD-10-CM · FY 2027
- Effective date
- Oct 1, 2026
- Publisher
- Vero Scribe Inc.
This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.
Frequently asked questions
What does ICD-10-CM code T78.4 mean?
T78.4 is the FY 2027 U.S. ICD-10-CM code for “Other and unspecified allergy.”
Is T78.4 a billable or specific ICD-10-CM code?
No. T78.4 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.
Where is T78.4 located in ICD-10-CM?
T78.4 is listed in Chapter 19, Injury, poisoning and certain other consequences of external causes (S00-T88), within Other and unspecified effects of external causes (T66-T78) (T66–T78), under category T78, Adverse effects, not elsewhere classified.
What coding notes are listed for T78.4?
No inclusion terms are listed for T78.4 in this reference record. No code-first instruction is listed. Excludes1 notes: specified types of allergic reaction such as:; allergic diarrhea (K52.29); allergic gastroenteritis and colitis (K52.29); dermatitis (L23-L25, L27.-); food protein-induced enterocolitis syndrome (K52.21); food protein-induced enteropathy (K52.22); hay fever (J30.1). No Excludes2 note is listed.