ICD-10 Code J01.1 – Acute frontal sinusitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J01.1 – Acute frontal sinusitis
What it is
J01.1 identifies an acute infection or inflammation of the frontal sinus. Use it when documentation specifically states frontal sinusitis and the episode is recent or short-term.
Clinical signs
Typical findings include frontal headache or pressure, nasal congestion, purulent drainage, and tenderness over the frontal sinus. Clinical features vary; refer to documentation.
When to use this code
Use J01.1 when the provider documents acute frontal sinusitis, acute infection of the frontal sinus, or equivalent wording. It fits cases with sudden onset and no indication that the condition is chronic or recurrent. If the note does not specify the sinus site, check documentation.
Do not use for
Do not use this code for chronic sinusitis, recurrent sinusitis, or sinusitis limited to another sinus location. If the record only says “sinusitis” without frontal involvement, you need clarification.
Coding tip
Code the documented sinus site exactly; frontal sinus involvement supports J01.1, while unspecified site requires a different code.