Dermatology Billing — Every Lesion Measured, Every Procedure Coded, Every Claim Paid
Dermatology billing lives and dies on documentation depth — the difference between a paid claim and a denied one is often a single missing measurement, a wrong destruction method, or a cosmetic vs medical distinction that was never clearly documented. Netix knows every rule so your dermatologists treat patients while we make sure every procedure gets paid.
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Lesion size & destruction method coded correctly
Cosmetic vs medical distinction handled every claim
Mohs surgery billing specialists
THE PROBLEM
Why Dermatology Practices Lose Revenue on Every Procedure Day
Dermatology billing errors are documentation errors — and they are expensive because dermatology procedures are high-value. Here is where the losses happen most consistently
Lesion measurement documentation is incomplete
Excision codes (11400–11646) are selected based on the size of the excised lesion including margins — not the lesion alone. If the pathology report shows a 0.8cm lesion but the physician excised with 0.3cm margins on each side, the correct measurement is 1.4cm — a different CPT code with higher reimbursement. Most practices code from the lesion size alone and systematically underbill every excision.
Destruction vs excision vs shave removal — wrong method billed
Three completely different code families, three completely different reimbursement levels, and the documentation must support whichever method is billed. Shave removal (11300–11313) is not excision (11400–11646) and not destruction (17000–17286). Billing the wrong family — either because the documentation is vague or the coder is guessing — means either a denial or a lower-value claim than the procedure actually performed.
Cosmetic vs medical distinction is the most litigated issue in dermatology billing
A lesion removed for cosmetic reasons is not covered by insurance. The same lesion removed because it is symptomatic, changing, or suspicious is a covered medical service. If the documentation does not clearly establish medical necessity — symptoms, clinical change, patient concern driving medical evaluation — the payer denies as cosmetic regardless of the diagnosis code billed. This is the most common and most preventable dermatology denial.
Multiple lesion billing rules are misapplied.
When multiple lesions are destroyed in the same session, the first lesion uses the primary code and additional lesions use add-on codes — with different rules depending on the destruction method (benign vs premalignant vs malignant). Most practices either underbill additional lesions or apply add-on codes incorrectly.
Mohs surgery billing complexity is underestimated
Mohs micrographic surgery (17311–17315) is billed per stage and per block — with tissue processing, interpretation, and repair all potentially separately billable. The surgical repair after Mohs (layered closure, adjacent tissue transfer, skin graft) adds significant value to the claim and is routinely underbilled or missed entirely.
Biopsy bundling errors cost revenue on every biopsy day
When a biopsy (11102–11107) leads to a decision for a more definitive procedure on the same day, bundling rules determine whether both are billable. When performed on separate lesions, both are billable. When performed on the same lesion as a prelude to immediate excision — bundling applies. Getting this wrong in either direction costs money or creates audit exposure.
OUR DERMATOLOGY BILLING SERVICES
What Netix Handles for Dermatology Practices
Lesion Excision Billing
Correct CPT code selection from the excision families (11400–11646) based on excised diameter including margins — benign vs malignant distinction, anatomic site selection, and documentation review to ensure the measurement in the note supports the code billed.
Destruction Billing
Benign lesion destruction (17110–17111), actinic keratosis destruction (17000–17004), and malignant lesion destruction (17260–17286) — primary code plus correct add-on application for multiple lesions, destruction method documented to support the code family billed.
Shave Removal Billing
Shave removal (11300–11313) by anatomic site and lesion size — correctly separated from excision and destruction, with documentation confirming the removal method used.
Biopsy Billing
Shave biopsy (11102–11103), punch biopsy (11104–11105), incisional biopsy (11106–11107) — correct method selection, multiple biopsy add-on application (11103, 11105, 11107), and bundling rules applied correctly when biopsy and excision occur same session same lesion.
Mohs Surgery Billing
Mohs micrographic surgery (17311–17315) billed per stage, per block, with correct tissue processing and interpretation included — plus surgical repair coding (layered closure, flap, graft) as a separately billable service after Mohs, which is one of the highest-value billing opportunities in dermatology.
Cosmetic vs Medical Documentation Review
Pre-submission documentation review on procedures with cosmetic vs medical ambiguity — flagging claims where the note does not adequately establish medical necessity before the claim goes out, not after it denies.
Acne & Injection Billing
Intralesional injection (11900–11901) by number of lesions, acne surgery (10040), photodynamic therapy (96567–96573) — correctly separated from E&M when performed same day with modifier 25.
Phototherapy Billing
UVB phototherapy (96910–96913), PUVA (96912), excimer laser (96920–96922) — per-session billing with correct code selection by therapy type and body surface area.
Cosmetic Procedure Billing (Patient Pay)
Botox, fillers, chemical peels, laser resurfacing — correctly identified as non-covered and billed directly to the patient at the correct fee schedule. Keeping cosmetic billing completely separate from insurance billing is a compliance requirement most practices handle inconsistently.
E&M Level Optimization
MDM-based E&M review for dermatology — complex multi-lesion evaluations, melanoma surveillance, skin cancer follow-up, and autoimmune skin disease management frequently support higher E&M levels than practices bill.
Prior Authorization Management
Biologic medications (dupilumab, secukinumab, ixekizumab), phototherapy, and certain laser procedures require prior auth — managed upfront before treatment begins, with step therapy documentation prepared for biologics.
Denial Management — Dermatology Specific
Cosmetic denials, medical necessity challenges on lesion removal, bundling disputes on same-day procedures, and measurement-based code downgrades — appealed with dermatology-specific clinical documentation and correct measurement evidence.
Dermatology Denial Prevention & Recovery
Dermatology claims can be denied because of unclear medical necessity, incorrect procedure bundling, missing measurements, or documentation that does not fully support the service billed. Reviewing recurring denial patterns helps identify these issues early, strengthen supporting documentation, and improve the chances of successful claim resolution.
LESION CODING EXPLAINED
Dermatology Lesion Coding — The Measurement Rules That Determine Your Reimbursement
The single most revenue-impactful billing rule in dermatology is lesion measurement — and it is misapplied in the direction of underbilling on a significant percentage of excision claims.
The rule for excisions:
Excision CPT codes are selected based on the greatest clinical diameter of the lesion PLUS the narrowest margin required for complete excision — measured at the time of surgery, not from the pathology report.
Example:
- Lesion diameter: 1.2cm
- Margin required: 0.4cm on each side
- Correct excision diameter: 1.2 + 0.4 + 0.4 = 2.0cm
- CPT code: based on 2.0cm, not 1.2cm
What most practices do wrong
Code from the lesion size on the pathology report — which reflects the specimen after it has been removed, not the excision diameter at the time of surgery. This systematic underbilling affects every excision on every procedure day.
Anatomic site matters too
Excision codes are divided by anatomic site — trunk/arms/legs (11400–11406), scalp/neck/hands/feet/genitalia (11420–11426), and face/ears/eyelids/nose/lips (11440–11446). Wrong site selection means wrong code regardless of size.
Benign vs malignant
Benign excisions (11400–11446) and malignant excisions (11600–11646) are separate code families with different reimbursement levels. The pathology result determines which applies — and claims sometimes need to be rebilled after pathology confirms malignancy.
What we do
Document measurement review on every excision claim before submission — comparing the operative note measurement to the CPT code selected, flagging undercoding, and correcting claims before they go out.
DERMATOLOGY CPT CODES WE KNOW COLD
Dermatology CPT Codes — Handled by Specialists
| CPT Code | Service | Common Issue |
|---|---|---|
| 11102 | Shave biopsy first lesion | Wrong method vs punch biopsy |
| 11103 | Shave biopsy add-on | Add-on missed on multiple biopsies |
| 11104 | Punch biopsy first lesion | Bundling with same-day excision |
| 11105 | Punch biopsy add-on | Multiple lesion add-on missed |
| 11300–11313 | Shave removal | Confused with excision coding |
| 11400–11406 | Excision benign trunk/arms/legs | Measurement undercoding |
| 11420–11426 | Excision benign scalp/neck | Wrong anatomic site selection |
| 11440–11446 | Excision benign face/ears | Margin calculation missed |
| 11600–11606 | Excision malignant trunk/arms | Benign vs malignant rebilling |
| 11620–11626 | Excision malignant scalp/neck | Post-pathology rebilling missed |
| 11640–11646 | Excision malignant face/ears | High-value — measurement critical |
| 17000 | Destruction AK first lesion | Wrong code family selected |
| 17003 | Destruction AK add-on | Add-on missed on multiple AKs |
| 17110 | Destruction benign 1–14 lesions | Count documentation missing |
| 17111 | Destruction benign 15+ lesions | Count threshold not documented |
| 17260–17286 | Destruction malignant lesions | Method and size documentation |
| 17311 | Mohs first stage head/neck | Stage and block count billing |
| 17312 | Mohs add-on stages head/neck | Add-on stages underbilled |
| 17313 | Mohs first stage trunk/arms | Site vs head/neck distinction |
| 11900 | Intralesional injection 7 or fewer | Lesion count documentation |
| 11901 | Intralesional injection 8+ | Count threshold not documented |
| 96920–96922 | Excimer laser | Body surface area documentation |
| 99202–99215 | Office E&M visits | Systematic undercoding |
MOHS SURGERY BILLING
Mohs Surgery Billing — Every Stage, Every Block, Every Repair
Mohs micrographic surgery is the highest-value procedure in dermatology — and the billing is proportionally complex.
How Mohs billing works:
Mohs is billed per stage (each time tissue is excised and examined) and per tissue block within each stage. The first stage on head/neck/hands/feet/genitalia (17311) covers the first 5 tissue blocks — additional blocks within stage 1 use add-on code 17315. Additional stages use 17312 (head/neck) or 17314 (trunk/extremities).
The repair after Mohs is separately billable:
The surgical repair of the Mohs defect — whether simple closure, layered closure (12031–12057), adjacent tissue transfer/flap (14000–14350), or skin graft (15100–15261) — is a separately billable service and one of the highest-value add-ons in all of dermatology. Most practices bill the Mohs correctly but underbill or miss the repair entirely.
Pathology processing:
The tissue processing and interpretation performed by the Mohs surgeon are included in the Mohs codes — they are not separately billable by the same physician. Billing separate pathology codes alongside Mohs by the same provider is a compliance error.
What we handle:
Stage and block count verification, repair code selection based on defect size and closure type, correct anatomic site assignment, and pre-submission audit to ensure every Mohs claim captures the full billable value of the procedure.
Who We Serve
Dermatology Providers We Work With
General dermatology practices
Full-service derm billing with excisions, destructions, biopsies, and E&M optimization
Mohs surgery practices
Stage, block, and repair billing with maximum capture on every case
Cosmetic dermatology
Patient-pay cosmetic billing completely separated from insurance billing
Pediatric dermatology
Medicaid billing, pediatric procedure documentation, school absence letter billing
Academic dermatology
Teaching physician rules, resident supervision modifiers
Multi-physician derm groups
Per-physician procedure reporting and consistent coding across all providers
Teledermatology practices
Asynchronous store-and-forward billing (G2010, G2012) and synchronous telehealth modifier compliance
RESULTS WE BUILD TOWARD
What Dermatology Billing Looks Like When It Works
First-pass clean claim rate: 96%+
Days in AR: under 32
Excision measurement accuracy: 100% pre-submission review
Cosmetic denial rate: under 1% (medical necessity documented before submission)
Mohs repair capture rate: 100% of qualifying defect repairs billed
Multiple lesion add-on capture: every add-on code applied on every qualifying visit
Monthly report: revenue per procedure category, per physician, per payer — with procedure mix analysis
Numbers based on industry benchmarks — your practice-specific results reported monthly.
FAQ
Dermatology Billing Questions
How should we measure lesions for excision coding?
The correct measurement is the greatest clinical diameter of the lesion plus the narrowest margin required for complete excision — measured at the time of surgery, not from the pathology report. If your current process codes from the pathology specimen size, you are systematically underbilling every excision. The free audit includes an excision measurement review.
What is the most common reason dermatology claims deny?
Cosmetic vs medical necessity — payers deny procedures where the documentation does not clearly establish that the removal was medically indicated rather than cosmetically motivated. The documentation must capture symptoms, clinical change, or medical concern explicitly. Diagnosis code alone is not enough.
We do a lot of AK destructions. Are we billing multiple lesions correctly?
AK destruction uses a primary code (17000) for the first lesion and an add-on code (17003) for lesions 2 through 14 — with 17004 used when 15 or more AKs are destroyed in a single session. The count of lesions destroyed must be documented in the operative note. If your notes say “multiple AKs destroyed” without a specific count, the additional lesions cannot be billed.
Can you handle Mohs surgery billing specifically?
Yes — stage and block count verification, repair code selection, anatomic site assignment, and pre-submission audit on every Mohs case. Mohs billing is one of our dermatology specializations.
How do we handle procedures that turn out to be cosmetic after the fact?
If a lesion is removed under a medical indication and pathology returns benign with no clinical significance, the claim was appropriately billed at the time based on the medical indication. If payer disputes, we appeal with the clinical documentation supporting the medical decision to remove at the time of service.
What makes dermatology billing harder than general medical billing?
The measurement-dependent code selection for excisions, destruction method and lesion count rules, cosmetic vs medical distinction, Mohs stage and block billing complexity, and the high procedure volume that makes systematic errors expensive fast. A general biller treats derm like any other procedure specialty — and that approach costs measurement accuracy on every excision.
The correct measurement is the greatest clinical diameter of the lesion plus the narrowest margin required for complete excision — measured at the time of surgery, not from the pathology report. If your current process codes from the pathology specimen size, you are systematically underbilling every excision. The free audit includes an excision measurement review.
Cosmetic vs medical necessity — payers deny procedures where the documentation does not clearly establish that the removal was medically indicated rather than cosmetically motivated. The documentation must capture symptoms, clinical change, or medical concern explicitly. Diagnosis code alone is not enough.
AK destruction uses a primary code (17000) for the first lesion and an add-on code (17003) for lesions 2 through 14 — with 17004 used when 15 or more AKs are destroyed in a single session. The count of lesions destroyed must be documented in the operative note. If your notes say “multiple AKs destroyed” without a specific count, the additional lesions cannot be billed.
Yes — stage and block count verification, repair code selection, anatomic site assignment, and pre-submission audit on every Mohs case. Mohs billing is one of our dermatology specializations.
If a lesion is removed under a medical indication and pathology returns benign with no clinical significance, the claim was appropriately billed at the time based on the medical indication. If payer disputes, we appeal with the clinical documentation supporting the medical decision to remove at the time of service.
The measurement-dependent code selection for excisions, destruction method and lesion count rules, cosmetic vs medical distinction, Mohs stage and block billing complexity, and the high procedure volume that makes systematic errors expensive fast. A general biller treats derm like any other procedure specialty — and that approach costs measurement accuracy on every excision.
Find Out How Much Revenue Your Dermatology Practice Loses Per Procedure Day
The free dermatology billing audit reviews your excision measurement process, destruction add-on capture, cosmetic denial patterns, Mohs repair billing, and E&M distribution — and shows you, in plain numbers, what every procedure day should be generating versus what it actually is.
Get My Free Dermatology Billing Audit
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