Dermatology billing has a structural complexity that no other specialty deals with: the same procedure can be cosmetic (patient pays) or medical (insurer pays) depending on the clinical indication — and sometimes that determination happens in the room, not before the patient is scheduled.
A shave removal of a benign seborrheic keratosis is cosmetic. A shave removal of a lesion that the dermatologist suspects may be premalignant is medical. The procedure is the same. The billing is completely different. The documentation determines which bucket it falls into.
Problem 1: Cosmetic vs. Medical Determination Errors
The decision rules are specific and not universally applied:
| Procedure | Cosmetic (patient pay) | Medical (insurer pay) |
|---|---|---|
| Lesion removal | Removal of benign lesion for cosmetic purposes (seborrheic keratosis, skin tags not causing symptoms) | Removal of potentially malignant lesion, symptomatic lesions, lesions on functionally significant areas |
| Chemical peel | Cosmetic skin resurfacing, wrinkle reduction | Treatment of actinic keratoses — billed as 17000-17004 |
| Cryotherapy | Cosmetic removal of benign lesions | Treatment of actinic keratoses (17000-17004), verruca (17110-17111), or medically indicated lesion removal |
| Botox | Aesthetic treatment | Treatment of hyperhidrosis (CPT 64650/64653) or certain medical indications — payer-specific coverage |
The billing error: applying medical codes to procedures that were performed for cosmetic indications (upcoding), or applying cosmetic designation to procedures that have legitimate medical indications and coverage (leaving money on the table). Both errors are systematic — they repeat on every encounter of the same type until someone catches the pattern.
Problem 2: Mohs Surgery Stage Billing
Mohs surgery is billed in stages, with each stage representing a layer of tissue excised and examined. The CPT codes are 17311–17315, with 17311 for the first stage of the first tumor and 17312 for each additional stage of the same tumor. Multiple tumors in the same session each start a new 17311.
The billing error pattern: billing all stages under a single code rather than correctly sequencing first-stage and additional-stage codes. Or billing the repair (13100–13160) incorrectly relative to the defect size — defect size at the time of repair, not the original lesion size, determines the repair code.
Mohs billing also has a documentation requirement: the Mohs map or layer-by-layer diagram must be in the record to support the number of stages billed. Audits on Mohs claims that find missing stage documentation generate take-back demands.
Problem 3: Biopsy vs. Excision Coding
The clinical decision to biopsy (sample tissue for diagnosis) versus excise (remove the entire lesion) determines which code set applies. Biopsy codes (11102–11107) are for sampling. Excision codes (11400–11646) are for complete removal. When a dermatologist biopsies a lesion and then schedules a full excision, both codes may be billable — but billing both in the same session requires a -58 modifier indicating staged procedures.
The error: billing excision codes for what was clinically a biopsy, or missing the excision entirely when a complete removal was performed but coded as a biopsy. The correct code depends on the intent and the pathology — documentation must support the choice.
Frequently Asked Questions
How do you determine if a dermatology procedure is cosmetic or medical for billing?
The determination is based on clinical indication, not procedure type. A procedure is medical when there is a clinical indication the insurer recognizes as covered — potential malignancy, symptomatic lesion, functional impairment, or a specific diagnosis with coverage. The same procedure is cosmetic when performed for appearance without a covered medical indication. The clinical documentation must support the determination — the biller codes based on the documented indication, not the patient’s reason for presenting.
How is Mohs surgery billed?
CPT 17311 for the first stage of the first tumor location. CPT 17312 for each additional stage of the same tumor. Multiple tumors each start a new 17311. The repair is billed separately based on defect size at time of repair (not original lesion size). Each stage must have a corresponding Mohs map or layer diagram in the procedure record to support the number of stages billed.
What is the difference between biopsy and excision billing in dermatology?
Biopsy codes (11102-11107) apply when a sample is taken for diagnosis — the lesion may not be completely removed. Excision codes (11400-11646) apply when the lesion is completely removed, billed by lesion diameter and location. If both are performed in the same session, the excision code typically replaces the biopsy code — billing both requires documentation showing the staged intent and a -58 modifier.
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Related Resources
Dermatology billing specialists | Systematic denial reduction | Billing audit guide
Our dermatology billing specialists handle Mohs surgery staging and cosmetic vs. medical billing determination. We serve dermatology practices in California, Florida, and Texas.