ICD-10 Code L42 – Pityriasis rosea (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L42 – Pityriasis rosea
What it is
L42 identifies pityriasis rosea, a self-limited skin eruption usually marked by oval, scaly patches. You use it when the documentation names this specific diagnosis.
Clinical signs
Typical findings include a herald patch followed by a generalized rash on the trunk and proximal limbs. Clinical features vary; refer to documentation.
When to use this code
Use L42 when the provider documents pityriasis rosea, including classic or atypical presentations. Apply it for confirmed outpatient or inpatient diagnoses when the record supports this specific eruption. If the note only says “rash” or “dermatitis,” check documentation before coding L42.
Do not use for
Do not use L42 for nonspecific eruptions, eczema, psoriasis, or fungal rashes. If the diagnosis is uncertain or different in the record, code the documented condition instead.
Coding tip
Look for the exact term “pityriasis rosea” in the assessment, not just a descriptive rash pattern.