ICD-10 Code A77 – Spotted fever [tick-borne rickettsioses] (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A77 – Spotted fever [tick-borne rickettsioses]
What it is
A77 identifies spotted fever group rickettsial infections transmitted by ticks. Use it for documented tick-borne rickettsiosis when the record does not specify a more exact subtype.
Clinical signs
Typical findings include fever, headache, rash, and a history of tick exposure. Clinical features vary; refer to documentation.
When to use this code
Use A77 when the provider documents spotted fever, tick-borne rickettsiosis, or a similar nonspecific rickettsial infection. It also fits cases where the organism is not named but the clinical diagnosis is clearly a tick-borne spotted fever group illness.
Confirm that the note supports an active infection rather than past exposure or screening. If the chart names a specific rickettsial disease, code that more precise diagnosis instead.
Do not use for
Do not use A77 for nonspecific fever, rash, or tick bite alone. Check documentation if the record points to another tick-borne illness or a different infectious cause.
Coding tip
Code the most specific rickettsial diagnosis documented; if the subtype is unclear, A77 is the appropriate fallback.