ICD-10 Code D47.02 – Systemic mastocytosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D47.02 – Systemic mastocytosis
What it is
D47.02 identifies systemic mastocytosis, a disorder in which mast cells accumulate in one or more internal organs. It is a systemic condition, not just a skin finding.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include flushing, itching, abdominal pain, diarrhea, bone pain, and symptoms from organ involvement.
When to use this code
Use D47.02 when the provider documents systemic mastocytosis or confirms mast cell disease involving extracutaneous organs. Code it from specialist notes, pathology reports, or a finalized diagnosis in the record. If the chart only mentions suspected mastocytosis, check documentation before assigning the code.
Do not use for
Do not use this code for isolated cutaneous mastocytosis or nonspecific allergic reactions. If the documentation does not confirm a systemic form, choose the more accurate diagnosis or check documentation.
Coding tip
Verify that the record explicitly supports systemic involvement before reporting D47.02.