ICD-10 Code A66.3 – Hyperkeratosis of yaws (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A66.3 – Hyperkeratosis of yaws
What it is
A66.3 identifies hyperkeratosis caused by yaws, a treponemal infection. Use it when documentation states thickened, wart-like skin changes attributed to yaws.
Clinical signs
Findings usually include localized or widespread thickening of the skin, especially on the palms or soles. Clinical features vary; refer to documentation.
When to use this code
Use A66.3 when the provider documents hyperkeratosis as a manifestation of yaws. It may appear in records describing chronic skin thickening or yaws-related keratotic lesions. If the note only says “hyperkeratosis” without yaws, check documentation before coding.
Do not use for
Do not use this code for hyperkeratosis from other causes, such as eczema, psoriasis, or friction. Do not assume yaws without explicit documentation.
Coding tip
Code the yaws manifestation only when the record links the keratosis to yaws; otherwise, query for clarification.