2024 ICD-10-CM Diagnosis Code T78.49XA

Other allergy, initial encounter

ICD-10-CM Code:
T78.49XA
ICD-10 Code for:
Other allergy, initial encounter
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Injury, poisoning and certain other consequences of external causes
    (S00–T88)
    • Other and unspecified effects of external causes
      (T66-T78)
      • Adverse effects, not elsewhere classified
        (T78)

T78.49XA is a billable diagnosis code used to specify a medical diagnosis of other allergy, initial encounter. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

T78.49XA is an initial encounter code, includes a 7th character and should be used while the patient is receiving active treatment for a condition like other allergy. According to ICD-10-CM Guidelines an "initial encounter" doesn't necessarily means "initial visit". The 7th character should be used when the patient is undergoing active treatment regardless if new or different providers saw the patient over the course of a treatment. The appropriate 7th character codes should also be used even if the patient delayed seeking treatment for a condition.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Allergic gingival disease
  • Allergic gingivitis
  • Allergic reaction to chemical
  • Allergic reaction to cosmetics
  • Allergic reaction to flour dust
  • Allergic reaction to insect bite
  • Allergic reaction to insect venom
  • Allergic reaction to plant, except food
  • Allergic reaction to radiocontrast media
  • Allergic reaction to tattoo ink
  • Allergic sensitization
  • Allergic sensitization by patch test
  • Allosensitization
  • Arthropathy associated with a hypersensitivity reaction
  • Atopic IgE-mediated allergic disorder
  • Cell-mediated cytotoxic disorder
  • Cell-mediated cytotoxic reaction
  • Cell-mediated immune reaction
  • Contact hypersensitivity
  • Contrast media adverse reaction
  • Delayed hypersensitivity disorder
  • Environmental allergy
  • Erythrocyte alloimmunization
  • Hypersensitivity disorder mediated by immune complex
  • Hypersensitivity gingivitis
  • IgE-mediated allergic disorder
  • Immune hypersensitivity disorder by mechanism
  • Jarisch Herxheimer reaction
  • Jones-Mote type hypersensitivity
  • Nonatopic IgE-mediated allergic disorder
  • Non-IgE-mediated allergic disorder
  • Non-IgE-mediated atopic disorder
  • Phacoanaphylaxis
  • Platinum sensitivity

Clinical Classification

Clinical Information

  • Contact Hypersensitivity

    contact hypersensitivity is an inflammatory response induced by antigen-reactive t cells that are exposed to antigen on the skin surface (epidermis). poison ivy is a frequent cause of such reactivity, due to the urushiol from the plant, as are a variety of antigens derived from industrial exposure (e.g. rubber, chromate, nickel). these antigens induce the appearance of th1-like t cells, which presumably produce ifn to activate macrophages.

Coding Guidelines

The appropriate 7th character is to be added to each code from block Adverse effects, not elsewhere classified (T78). Use the following options for the aplicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Convert T78.49XA to ICD-9-CM

  • ICD-9-CM Code: 995.3 - Allergy, unspecified
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Patient Education


Allergy

An allergy is a reaction by 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

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. Genes and the environment probably both play a role.

Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Allergies can range from minor to severe. Anaphylaxis is a severe reaction that can be life-threatening. Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions.


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.