ICD-10 Code L05 – Pilonidal cyst and sinus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L05 – Pilonidal cyst and sinus
What it is
L05 identifies a pilonidal cyst or sinus, usually a small tract or cyst near the tailbone. It commonly contains hair and debris and may become inflamed or infected.
Clinical signs
Typical findings include pain, swelling, redness, or drainage in the sacrococcygeal area. Clinical features vary; refer to documentation for whether the lesion is cyst, sinus, or abscess.
When to use this code
Use L05 when the provider documents pilonidal cyst, pilonidal sinus, or pilonidal disease at the natal cleft or sacrococcygeal region. It also fits encounters for evaluation of a documented pilonidal tract, even if currently not infected. Check documentation if the record only says perianal or skin abscess.
Do not use for
Do not assign this code for unrelated anal, rectal, or general skin infections without pilonidal documentation. If the note does not clearly identify a pilonidal lesion, check documentation.
Coding tip
Code the pilonidal condition from the provider’s exact wording and confirm the anatomic site before assigning L05.