ICD-10 Code for Skin Reaction Due to Topical Fluorouracil
The appropriate ICD-10 code for a skin reaction due to topical fluorouracil is L27.0 (Generalized skin eruption due to drugs and medicaments taken internally) or L23.9 (Allergic contact dermatitis, unspecified cause) depending on whether the reaction is systemic or localized contact dermatitis.
Coding Considerations
Primary Code Selection
For localized irritant contact dermatitis at the application site (the most common reaction), use L24.9 (Irritant contact dermatitis, unspecified cause) as this represents the anticipated pharmacological effect of topical 5-fluorouracil 1.
For allergic contact dermatitis confirmed by patch testing or clinical presentation, use L23.9 (Allergic contact dermatitis, unspecified) or L23.5 (Allergic contact dermatitis due to other chemical products) 1.
For distant skin reactions (such as seborrheic dermatitis-like eruptions or scrotal dermatitis occurring away from application sites), use L27.0 (Generalized skin eruption due to drugs and medicaments) as these represent systemic absorption effects 2, 3.
Secondary Codes
T45.1X5A (Adverse effect of antineoplastic and immunosuppressive drugs, initial encounter) should be added as a secondary code to identify the causative agent 1.
For severe reactions requiring hospitalization (such as necrotizing inflammatory reactions with ulceration), consider adding L51.9 (Erythema multiforme, unspecified) if bullous changes are present 4.
Specific Clinical Scenarios
Local reactions at application site (burning, crusting, erythema, ulceration):
- Primary: L24.9 (Irritant contact dermatitis)
- Secondary: T45.1X5A (Adverse effect of antineoplastic drugs) 1
Distant skin reactions (facial seborrheic dermatitis, scrotal dermatitis):
Severe necrotizing reactions with ulceration:
- Primary: L51.9 (Erythema multiforme) or L98.9 (Disorder of skin and subcutaneous tissue, unspecified)
- Secondary: T45.1X5A 4
Pustular hypersensitivity reactions:
- Primary: L23.9 (Allergic contact dermatitis)
- Secondary: T45.1X5A 5
Documentation Requirements
- Document the specific type of reaction (irritant vs. allergic, local vs. distant) 1.
- Note the body site affected and whether it corresponds to the application site 2, 3.
- Record severity using CTCAE grading if applicable for oncology patients 6.
- Include timing of reaction onset relative to treatment initiation 7.