ICD-10 Code J01.00 – Acute maxillary sinusitis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J01.00 – Acute maxillary sinusitis, unspecified
What it is
This code identifies an acute infection or inflammation of the maxillary sinus when the provider does not document a specific cause or laterality. Use it for a current, short-term sinusitis episode involving the cheek sinus.
Clinical signs
Common findings include facial pain or pressure over the maxillary area, nasal congestion, and purulent drainage. Clinical features vary; refer to documentation for the exact presentation and whether the diagnosis is confirmed.
When to use this code
Use J01.00 when the record clearly states acute maxillary sinusitis but does not specify whether it is right, left, or bilateral. It also fits when the provider documents sinusitis of the maxillary sinus without further detail. If laterality or a different sinus is documented, choose the more specific code.
Do not use for
Do not use this code for chronic sinusitis, allergic rhinitis, or sinus symptoms without a documented diagnosis. Check documentation if the record identifies another sinus, a recurrent pattern, or a more specific cause.
Coding tip
Review the note for laterality and sinus location first; if either is missing, J01.00 may be appropriate.