ICD-10 Code L51 – Erythema multiforme (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L51 – Erythema multiforme
What it is
L51 identifies erythema multiforme, an acute inflammatory skin condition marked by target-like lesions. It may involve the skin alone or include mucous membranes, depending on severity.
Clinical signs
Typical findings include round, target or iris lesions, often on the extremities. Clinical features vary; refer to documentation if mucosal involvement, blistering, or systemic symptoms are not clearly stated.
When to use this code
Use L51 when the provider documents erythema multiforme without a more specific subtype. It is appropriate for confirmed cases with characteristic lesions. If the record specifies a related condition or cause, code the documented diagnosis instead.
Do not use for
Do not use this code for nonspecific rashes, urticaria, or Stevens-Johnson syndrome unless erythema multiforme is explicitly documented. Check documentation when the diagnosis is uncertain.
Coding tip
Code from the provider’s stated diagnosis and note any mucosal involvement or subtype if documented.