ICD-10 Code B65.3 – Cercarial dermatitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B65.3 – Cercarial dermatitis
What it is
B65.3 identifies cercarial dermatitis, also called swimmer’s itch. It is an itchy skin reaction caused by exposure to parasitic cercariae in contaminated freshwater or saltwater.
Clinical signs
Typical findings include sudden itching, redness, and small papules or bumps on exposed skin after water contact. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents cercarial dermatitis, swimmer’s itch, or a similar parasitic skin reaction. It is appropriate when the diagnosis is confirmed clinically after relevant water exposure. If the note only describes a rash without linking it to cercariae, check documentation.
Do not use for
Do not use B65.3 for nonspecific dermatitis, contact dermatitis, or other insect bites unless the provider specifically identifies cercarial dermatitis. Check documentation when the cause is unclear.
Coding tip
Look for a documented exposure history plus a provider statement linking the rash to cercarial dermatitis before assigning B65.3.