ICD-10 Code L56.4 – Polymorphous light eruption (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L56.4 – Polymorphous light eruption
What it is
Polymorphous light eruption is a skin reaction triggered by sun or ultraviolet exposure. It is a photosensitive condition that causes an abnormal rash after light exposure.
Clinical signs
Typical findings include an itchy or burning rash appearing on sun-exposed skin after outdoor exposure. Clinical features vary; refer to documentation.
When to use this code
Use L56.4 when the provider documents polymorphous light eruption, polymorphic light eruption, or a clearly equivalent diagnosis. Code it when the record links the rash to sunlight or ultraviolet exposure and the condition is not better described by another photodermatosis.
Do not use for
Do not use this code for ordinary sunburn, photoallergic dermatitis, or unspecified rash without a documented light-induced diagnosis. Check documentation.
Coding tip
Confirm that the note names polymorphous light eruption and documents the light trigger before assigning L56.4.