A66.3 ICD-10-CM Code: Hyperkeratosis of yaws
A66.3 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · HCC Buddy coding tools
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Other spirochetal diseases (A65-A69)
A66.3
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceHyperkeratosis of yaws
Hyperkeratosis of yaws is a skin condition caused by the yaws infection (a tropical disease spread by bacteria) that results in thickened, hardened patches of skin. This represents a specific manifestation of the yaws disease affecting the outer layer of the skin.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Ghoul hand
- Hyperkeratosis, palmar or plantar (early) (late) due to yaws
- Worm-eaten soles
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A66.3 in this effective period.
Related Child Codes
Includes
Official- bouba
- frambesia (tropica)
- pian
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A66.3 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A66.3 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A66.3 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A66.3 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is A66.3 an HCC code?
No. A66.3 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- A66.3
- Description
- Hyperkeratosis of yaws
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
Get the V28 RAF + MEAT cheat sheet
One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.
Free PDF. No card. Unsubscribe anytime.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A66.3 is the ICD-10-CM diagnosis code for hyperkeratosis of yaws. Hyperkeratosis of yaws is a skin condition caused by the yaws infection (a tropical disease spread by bacteria) that results in thickened, hardened patches of skin. This represents a specific manifestation of the yaws disease affecting the outer layer of the skin. A66.3 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other spirochetal diseases (a65-a69).
A66.3 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify that the patient has a confirmed diagnosis of yaws (caused by Treponema pallidum subspecies pertenue) with documented hyperkeratotic skin lesions before assigning this code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A66.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that the patient has a confirmed diagnosis of yaws (caused by Treponema pallidum subspecies pertenue) with documented hyperkeratotic skin lesions before assigning this code
- •This code should only be used when hyperkeratosis is specifically documented as a manifestation of yaws; do not use for hyperkeratosis from other causes