2020 ICD-10-CM Diagnosis Code T78.4

Other and unspecified allergy

    2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
  • T78.4 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2020 edition of ICD-10-CM T78.4 became effective on October 1, 2019.
  • This is the American ICD-10-CM version of T78.4 - other international versions of ICD-10 T78.4 may differ.
Type 1 Excludes
Type 1 Excludes Help
A type 1 excludes note is a pure excludes. It means "not coded here". A type 1 excludes note indicates that the code excluded should never be used at the same time as T78.4. A type 1 excludes note is for used for when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • specified types of allergic reaction such as:
  • allergic diarrhea (
    ICD-10-CM Diagnosis Code K52.29

    Other allergic and dietetic gastroenteritis and colitis

      2017 - New Code 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Food hypersensitivity gastroenteritis or colitis
    • Immediate gastrointestinal hypersensitivity
    K52.29
    )
  • allergic gastroenteritis and colitis (
    ICD-10-CM Diagnosis Code K52.29

    Other allergic and dietetic gastroenteritis and colitis

      2017 - New Code 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Food hypersensitivity gastroenteritis or colitis
    • Immediate gastrointestinal hypersensitivity
    K52.29
    )
  • dermatitis (
    ICD-10-CM Diagnosis Code L23

    Allergic contact dermatitis

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    Type 2 Excludes
    • dermatitis due to substances taken internally (L27.-)
    • dermatitis of eyelid (H01.1-)
    • diaper dermatitis (L22)
    • eczema of external ear (H60.5-)
    • irritant contact dermatitis (L24.-)
    • perioral dermatitis (L71.0)
    • radiation-related disorders of the skin and subcutaneous tissue (L55-L59)
    L23
    -
    ICD-10-CM Diagnosis Code L25

    Unspecified contact dermatitis

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • allergic contact dermatitis (L23.-)
    • allergy NOS (T78.40)
    • dermatitis NOS (L30.9)
    • irritant contact dermatitis (L24.-)
    Type 2 Excludes
    • dermatitis due to ingested substances (L27.-)
    • dermatitis of eyelid (H01.1-)
    • eczema of external ear (H60.5-)
    • perioral dermatitis (L71.0)
    • radiation-related disorders of the skin and subcutaneous tissue (L55-L59)
    L25
    ,
    ICD-10-CM Diagnosis Code L27
    • L27 Dermatitis due to substances taken internally...
      • L27.0 Generalized skin eruption due to drugs and me...
      • L27.1 Localized skin eruption due to drugs and medi...
      • L27.2 Dermatitis due to ingested food
      • L27.8 Dermatitis due to other substances taken inte...
      • L27.9 Dermatitis due to unspecified substance taken...
    L27.-
    )
  • food protein-induced enterocolitis syndrome (
    ICD-10-CM Diagnosis Code K52.21

    Food protein-induced enterocolitis syndrome

      2017 - New Code 2018 2019 2020 Billable/Specific Code
    Applicable To
    • FPIES
    Use Additional
    • code for hypovolemic shock, if present (R57.1)
    K52.21
    )
  • food protein-induced enteropathy (
    ICD-10-CM Diagnosis Code K52.22

    Food protein-induced enteropathy

      2017 - New Code 2018 2019 2020 Billable/Specific Code
    K52.22
    )
  • hay fever (
    ICD-10-CM Diagnosis Code J30.1

    Allergic rhinitis due to pollen

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Allergy NOS due to pollen
    • Hay fever
    • Pollinosis
    J30.1
    )
The following code(s) above T78.4 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to T78.4:
  • S00-T88
    2020 ICD-10-CM Range S00-T88

    Injury, poisoning and certain other consequences of external causes

    Note
    • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
    Type 1 Excludes
    Use Additional
    • code to identify any retained foreign body, if applicable (Z18.-)
    Injury, poisoning and certain other consequences of external causes
  • T78
    ICD-10-CM Diagnosis Code T78

    Adverse effects, not elsewhere classified

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 2 Excludes
    • complications of surgical and medical care NEC (T80-T88)
    Adverse effects, not elsewhere classified
Clinical Information
  • A disorder characterized by an adverse local or general response from exposure to an allergen.
  • A local or general reaction of an organism following contact with a specific allergen to which it has been previously exposed and to which it has become sensitized.
  • Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.
  • An allergy is a reaction of your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are
    • pollen
    • dust mites
    • mold spores
    • pet dander
    • food
    • insect stings
    • medicines
    how do you get allergies? scientists think both genes and the environment have something to do with it. Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm.allergies can cause a runny nose, sneezing, itching, rashes, swelling or asthma. Symptoms vary. Although allergies can make you feel bad, they usually won't kill you. However, a severe reaction called anaphylaxis is life-threatening.
  • An exaggerated response by the immune system to a drug or other substance.
  • An inflammatory response to an exogenous environmental antigen or an endogenous antigen initiated by the adaptive immune system. [goc:jal, isbn:0781735149 "fundamental immunology"]
  • An inflammatory response to an exogenous environmental antigen or an endogenous antigen initiated by the adaptive immune system. [goc:jal, isbn:0781735149]
  • Functions of the body's response of increased sensitization to foreign substances, such as in sensitivities to different antigens.
  • Hypersensitivity to an agent caused by an immunologic response to an initial exposure
  • Hypersensitivity; a local or general reaction of an organism following contact with a specific allergen to which it has been previously exposed and to which it has become sensitized.
  • Known to have allergic reactions to particular substance(s)
  • State of previously immunized body in which tissue damage results from the immune response to a further dose of antigen.
Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
ICD-10-CM Codes Adjacent To T78.4
T78.1XXD …… subsequent encounter
T78.1XXS …… sequela
T78.2 Anaphylactic shock, unspecified
T78.2XXA …… initial encounter
T78.2XXD …… subsequent encounter
T78.2XXS …… sequela
T78.3 Angioneurotic edema
T78.3XXA …… initial encounter
T78.3XXD …… subsequent encounter
T78.3XXS …… sequela
T78.4 Other and unspecified allergy
T78.40 Allergy, unspecified
T78.40XA …… initial encounter
T78.40XD …… subsequent encounter
T78.40XS …… sequela
T78.41 Arthus phenomenon
T78.41XA …… initial encounter
T78.41XD …… subsequent encounter
T78.41XS …… sequela
T78.49 Other allergy
T78.49XA …… initial encounter

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.