ICD-10-CM 2027
ICD-10 code for milk protein allergy
From the official ICD-10-CM alphabetic index entry “Allergy, allergic (reaction) (to) › milk protein”. Page updated September 29, 2026.
About coding milk protein allergy
The ICD-10-CM code for milk protein allergy is Z91.0110 (Allergy to milk products, unspecified). The official index lists 16 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on Z91.0110.
Within Z91.011, choose Z91.0110 (unspecified) only when documentation doesn't support a more specific option: with tolerance to baked milk (Z91.0111) and with reactivity to baked milk (Z91.0112).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific milk protein allergy codes (official index)
- with
- reactivity to baked milk Z91.0112 — Allergy to milk products with reactivity to baked milk
- tolerance to baked milk Z91.0111 — Allergy to milk products with tolerance to baked milk
- adverse reaction NEC T78.119 — Other adverse food reaction due to milk and dairy products with baked milk tolerance/reactivity, unspecified
- with
- reactivity to baked milk T78.111 — Other adverse food reaction due to milk and dairy products with reactivity to baked milk
- tolerance to baked milk T78.110 — Other adverse food reactions due to milk and dairy products with tolerance to baked milk
- anaphylactic reaction T78.079 — Anaphylactic reaction due to milk and dairy products, unspecified
- with
- reactivity to baked milk T78.071 — Anaphylactic reaction due to milk and dairy products with reactivity to baked milk
- tolerance to baked milk T78.070 — Anaphylactic reaction due to milk and dairy products with tolerance to baked milk
- dermatitis L27.2 — Dermatitis due to ingested food
- enterocolitis syndrome K52.21 — Food protein-induced enterocolitis syndrome
- enteropathy K52.22 — Food protein-induced enteropathy
- gastroenteritis K52.29 — Other allergic and dietetic gastroenteritis and colitis
- gastroesophageal reflux K21.9 — Gastro-esophageal reflux disease without esophagitis
- with esophagitis (without bleeding) K21.00 — Gastro-esophageal reflux disease with esophagitis, without bleeding
- with bleeding K21.01 — Gastro-esophageal reflux disease with esophagitis, with bleeding
- proctocolitis K52.29 — Other allergic and dietetic gastroenteritis and colitis
Common questions about milk protein allergy ICD-10 codes
What is the ICD-10 code for milk protein allergy?
- Z91.0110 — Allergy to milk products, unspecified. More specific codes apply when the documentation supports them: Z91.0112, Z91.0111, T78.119, T78.111 and others below.
What is the ICD-10 code for adverse reaction nec milk protein allergy?
- T78.119 — Other adverse food reaction due to milk and dairy products with baked milk tolerance/reactivity, unspecified (header code; choose a more specific subcode).
What is the ICD-10 code for anaphylactic reaction milk protein allergy?
- T78.079 — Anaphylactic reaction due to milk and dairy products, unspecified (header code; choose a more specific subcode).
What is the ICD-10 code for dermatitis milk protein allergy?
- L27.2 — Dermatitis due to ingested food.
What is the ICD-10 code for enterocolitis syndrome milk protein allergy?
- K52.21 — Food protein-induced enterocolitis syndrome.
What is the ICD-10 code for enteropathy milk protein allergy?
- K52.22 — Food protein-induced enteropathy.
What is the ICD-10 code for gastroenteritis milk protein allergy?
- K52.29 — Other allergic and dietetic gastroenteritis and colitis.
Is Z91.0110 billable?
- Yes. Z91.0110 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Z91.0110 be used as a principal diagnosis?
- No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.
Is Z91.0110 a CC or MCC?
- No. Z91.0110 is neither a CC nor an MCC under MS-DRG v44.0.