ICD-10 Code A66.0 – Initial lesions of yaws (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A66.0 – Initial lesions of yaws
What it is
A66.0 identifies the earliest skin lesion of yaws, a contagious treponemal infection. Use it when documentation specifies the initial lesion stage rather than later or latent disease.
Clinical signs
Clinical features vary; refer to documentation. The initial lesion is typically a localized skin sore or papule at the inoculation site, sometimes with nearby lymph node enlargement.
When to use this code
Use A66.0 when the provider documents initial, primary, or early cutaneous lesions of yaws. It applies when the record clearly links the lesion to yaws infection and does not describe secondary or late manifestations.
If the note only says “yaws” without staging, check documentation before coding. Do not infer this code from nonspecific ulcers or skin lesions.
Do not use for
Do not use this code for latent, relapsing, or late yaws. It is also wrong for skin ulcers or tropical sores when yaws is not documented.
Coding tip
Stage matters: code A66.0 only when the record clearly identifies the initial lesion of yaws.