ICD-10 Code L27.9 – Dermatitis due to unspecified substance taken internally (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L27.9 – Dermatitis due to unspecified substance taken internally
What it is
L27.9 identifies dermatitis caused by an internally taken substance when the exact agent is not specified. Use it for a skin reaction linked to ingestion, but where the documentation does not name the substance.
Clinical signs
Clinical features vary; refer to documentation. Typical dermatitis findings may include erythema, itching, rash, or irritation, but the record should support a reaction after internal exposure.
When to use this code
Use this code when the clinician documents dermatitis from something taken by mouth or otherwise internally, and the substance is unspecified. It fits cases where the reaction is attributed to an internal exposure but the exact cause is not identified. Check documentation if the note is vague.
Do not use for
Do not use L27.9 for contact dermatitis from external exposure or for a clearly identified drug or food reaction that has a more specific code. If the substance is named, code it more precisely.
Coding tip
Confirm that the reaction is documented as internal and unspecified before assigning L27.9.