ICD-10 Code L56.1 – Drug photoallergic response (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L56.1 – Drug photoallergic response
What it is
L56.1 identifies a photoallergic skin reaction caused by a drug after exposure to sunlight or ultraviolet light. It is a delayed hypersensitivity reaction, so the rash appears after the medication and light exposure combine.
Clinical signs
Typical findings include itchy, eczematous, or dermatitis-like eruptions on sun-exposed skin. Clinical features vary; refer to documentation for the exact drug, timing, and distribution.
When to use this code
Use this code when the provider documents a drug-induced photoallergic reaction, photodermatitis, or similar diagnosis linked to medication and light exposure. Code it when the record clearly supports a photoallergic mechanism rather than a simple sunburn or nonspecific rash. Check documentation if the causative drug is not specified.
Do not use for
Do not use this code for ordinary phototoxic reactions, sunburn, or unspecified drug eruptions without photoallergic features. If the chart does not confirm a photoallergic response, use the documented condition instead.
Coding tip
Confirm both the medication trigger and the sunlight-related photoallergic reaction in the note before assigning L56.1.