ICD-10 Code B35.9 – Dermatophytosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B35.9 – Dermatophytosis, unspecified
What it is
B35.9 identifies a fungal infection caused by dermatophytes when the specific body site is not documented. Use it for ringworm-type infections that are confirmed or suspected, but not further specified.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include a scaly, itchy, annular rash or hair, skin, or nail involvement consistent with dermatophyte infection.
When to use this code
Use B35.9 when the record states dermatophytosis, tinea, or ringworm without identifying the affected site. It also fits when the provider confirms a dermatophyte infection but does not document a more specific codeable form. If the site is known, choose the more specific code instead.
Do not use for
Do not use this code for candidiasis, pityriasis versicolor, or other non-dermatophyte fungal infections. Avoid it when documentation supports a specific tinea site or a different skin diagnosis.
Coding tip
Check the note for the exact fungal site and organism description before defaulting to B35.9.