Dermatology ICD-10-CM codes

Actinic keratosis (L57.0) is the single most reported dermatology diagnosis, driving destruction and cryotherapy volume. Seborrheic keratosis splits into L82.0 (inflamed) and L82.1 (other); the inflamed code supports medical necessity for removal, so the documentation must state inflammation or irritation, not cosmetic concern.

Lesion-of-uncertain-nature coding follows the biopsy timeline. Before pathology, code the presenting lesion (D22.9 for a nevus, D23.9 for another benign neoplasm, or a symptom code); D48.5 (neoplasm of uncertain behavior of skin) is a pathologic diagnosis and should only be assigned after the pathologist reports uncertain behavior. Once malignancy is confirmed, use the site-specific C44 codes; C44.91 (basal cell) and C44.92 (squamous cell) are the unspecified-site fallbacks, and C43.9 covers melanoma when site is not documented.

Inflammatory dermatoses make up the medical clinic base: acne vulgaris (L70.0), rosacea (L71.9, or L71.0 perioral dermatitis), psoriasis vulgaris (L40.0), and the dermatitis family, where atopic dermatitis (L20.9) should be distinguished from unspecified dermatitis (L30.9) because biologic prior authorizations require the specific diagnosis. For biologic and systemic therapy patients, add the long-term drug monitoring context and code the disease at every visit even when stable.