ICD-10 Code A77.1 – Spotted fever due to Rickettsia conorii (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A77.1 – Spotted fever due to Rickettsia conorii
What it is
A77.1 identifies spotted fever caused by Rickettsia conorii, a tick-borne rickettsial infection. Use it when the provider documents this specific organism or diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Typical spotted fever illness may include acute fever, headache, rash, and a history of tick exposure, but coding depends on the documented diagnosis.
When to use this code
Use A77.1 when the record clearly states spotted fever due to Rickettsia conorii, including confirmed or clinically diagnosed cases. It also applies when the provider links the illness to this organism in the assessment or discharge summary.
If the chart only says “spotted fever,” “rickettsial infection,” or “tick-borne fever” without naming Rickettsia conorii, check documentation before assigning this code. You should code the most specific documented cause.
Do not use for
Do not use A77.1 for other spotted fevers or unspecified rickettsioses unless Rickettsia conorii is documented. Do not use it when the diagnosis is only suspected and not supported in the record.
Coding tip
Look for the exact organism name in provider documentation; specificity matters for this code.