2026 ICD-10-CM Diagnosis Code S20.169AInsect bite (nonvenomous) of breast, unspecified breast, initial encounter
S20.169A is a billable ICD-10-CM diagnosis code for insect bite (nonvenomous) of breast, unspecified breast, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 606 through 607, 963 through 965. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Superficial injury; contusion, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Bite wound of anterior chest wall
- Insect bite, nonvenomous, of breast
- Nonvenomous insect bite of breast with infection
- Nonvenomous insect bite of breast without infection
- Nonvenomous insect bite of chest wall with infection
- Nonvenomous insect bite of chest wall without infection
- Nonvenomous insect bite of trunk without infection
- Superficial injury of breast without infection
- Superficial injury of chest wall without infection
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Superficial injury of thorax (S20). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Insect Bites and Stings
Most insect bites are harmless, though they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito and flea bites usually itch. Insects can also spread diseases. In the United States, some mosquitoes spread West Nile virus.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S20.169A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S20.169AOverview
Is S20.169A (Insect bite (nonvenomous) of breast, unspecified breast) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report insect bite (nonvenomous) of breast, unspecified breast, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S20.169A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for insect bite (nonvenomous) of breast, unspecified breast, such as an emergency visit or first evaluation.
What MS-DRG does S20.169A group to?
When insect bite (nonvenomous) of breast, unspecified breast, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 606, 607, 963, 964, 965, with relative weights from 0.9064 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of S20.169A?
Under the General Equivalence Mappings, insect bite (nonvenomous) of breast, unspecified breast, initial encounter converts to ICD-9-CM 911.4 (insect bite trunk). The mapping is approximate, so confirm the match fits the documentation.
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.
