ICD-10 Code A66.9 – Yaws, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A66.9 – Yaws, unspecified
What it is
A66.9 identifies yaws when the record does not specify the stage or exact manifestation. Use it for this chronic infectious disease when documentation only states “yaws, unspecified.”
Clinical signs
Clinical features vary; refer to documentation. Yaws may present with skin lesions and, in later disease, bone or joint involvement, but you should code only what is documented.
When to use this code
Use A66.9 when the provider diagnoses yaws but does not document whether it is primary, secondary, or latent. It also fits when the note confirms yaws without enough detail for a more specific code.
Choose this code for problem lists, encounter diagnoses, or claims where the only supported statement is unspecified yaws. If the chart later identifies a specific stage, update the code accordingly.
Do not use for
Do not use A66.9 if the record clearly identifies another yaws stage or a different treponemal infection. Check documentation when the diagnosis is uncertain or only suspected.
Coding tip
Code the most specific yaws stage documented; use A66.9 only when stage details are missing.