Anonychia

This code represents the congenital absence of one or more nails, a rare developmental anomaly. It can affect fingernails, toenails, or both, and may occur as an isolated finding or as part of a broader syndrome. The condition is present at birth and is characterized by the complete lack of nail plate formation.

Use this code when documentation clearly indicates the congenital absence of nails. This diagnosis is typically made at birth or early infancy upon physical examination. Supporting documentation should specify the affected digits and confirm the congenital nature of the anonychia.

• Ensure documentation specifies "congenital" to differentiate from acquired nail loss.
• Review the patient's medical history for any associated syndromes, especially those involving skeletal or renal abnormalities.
• Remember the Excludes1 note for nail-patella syndrome (Q87.2); these conditions are never coded together.