What Is Dermatology Billing?
Dermatology billing is the specialty discipline of coding skin biopsies under the 2019 CPT restructure (11102 tangential, 11104 punch, 11106 incisional with 11103/11105/11107 add-ons), Mohs surgery by region (17311/17312 head/neck/hands/feet/genitalia, 17313/17314 trunk/extremities), destruction (17000 series), excision (11400-11646 sized in 0.5cm increments), phototherapy (96900/96910/96912), and biologic J-codes (Dupixent J2796, Skyrizi J2326, Cosentyx J3245, Tremfya J1628). Modifier 25 discipline on same-day E/M-plus-procedure is the top audit target.
- Biopsy primary by deepest technique, then add-ons stack across sites
- Mohs slide count must equal billed stages (UHC reviews >4 stages)
- Cigna automatic review on biopsy counts above six per visit
- Modifier 25 over ~60% of procedure visits triggers payer audits
Dermatology Billing Services
A four-provider dermatology group running 800 biopsies and 25 Mohs cases a month routinely leaks $30,000 to $45,000 monthly through modifier 25 audits, J-code substitution errors on biologics, and Cigna's appropriate-use review on biopsy counts above six per visit. That is the daily reality of dermatology billing — a specialty where the 2019 CPT restructure replaced the single 11100 biopsy code with the 11102/11104/11106 technique-specific family, where Mohs surgeons bill both stages (17311/17313) and same-day repair (12001-13160) in a sequence payers actively police, and where the difference between D23.x (benign) and C44.x (carcinoma) on the chief complaint determines whether the entire encounter clears or denies. Layer in patch-test unit caps under CPT 95044 (billed up to ~80 units per session), J-code precision on Dupixent (J2796), Skyrizi (J2326), and Cosentyx (J3245), UnitedHealthcare's Optum review on Mohs cases above four stages, and the 2024 CMS final rule on bundled dermatology payments — and small documentation gaps translate into denied claims on procedures that took place exactly as billed. This page covers how dermatology billing actually plays out across biopsies, Mohs, destruction and excision, phototherapy, biologics, and teledermatology.
Who This Page Is For
Common Billing Friction in Dermatology
Modifier 25 audit pressure on same-day E/M and procedure
Modifier 25 — appended to an E/M when a significant separately identifiable evaluation occurs the same day as a biopsy or destruction — sits at the top of every commercial-payer dermatology audit list. UnitedHealthcare's Optum and Cigna both run automated edits flagging practices where modifier 25 attaches to more than ~60% of procedure visits. The fix is documentation discipline: the E/M note must show a separate chief complaint, history, and assessment unrelated to the lesion being treated, with a stand-alone MDM that does not reference the procedure. Practices without this pattern lose roughly $95–$140 per stripped E/M.
Biopsy stacking under the 11102–11107 family and Cigna's six-biopsy review
The 2019 CPT restructure split skin biopsy by technique: tangential lands on 11102 (first) plus 11103 (each additional), punch on 11104 plus 11105, incisional on 11106 plus 11107. The primary code is determined by the deepest technique used in the session, then add-ons stack across all sites regardless of technique. Cigna's appropriate-use review automatically holds claims with more than six biopsies per visit pending records request, and Medicare MACs apply NCCI edits when a destruction (17000) and biopsy (11102) are billed at the same anatomic site without modifier 59 or XS.
Mohs sequencing: 17311/17313, the same-day repair rule, and UHC's four-stage review
Mohs is region-coded: 17311 covers head/neck, hands, feet, and genitalia first stage with 17312 for each additional stage at the same site, while 17313 covers trunk/extremities first stage with 17314 for additional stages. The Mohs surgeon — when also performing the repair — bills 17311/17313, the additional-stage codes, and the repair (12001–13160) on the same claim. UnitedHealthcare's Optum medical-policy review pulls Mohs cases with more than four stages per tumor for documentation review, and pathology slide counts in the operative report must match billed stages exactly.
Biologic J-codes and the buy-and-bill versus assignment-of-benefits split
Dermatology biologics have largely moved off J3590 (unclassified) onto specific J-codes: Dupixent (J2796), Skyrizi (J2326, established 2021), Tremfya (J1628), Cosentyx (J3245). Practices still billing J3590 with NDC pass-through risk MUE denials and incorrect average sales price reimbursement. The buy-and-bill model — where the practice purchases drug and bills the payer — only works when the patient's plan does not require specialty pharmacy distribution. Commercial plans increasingly route Skyrizi and Tremfya through assignment-of-benefits with specialty pharmacy, leaving practices with $4,000–$15,000 per dose in inventory exposure if buy-and-bill is used incorrectly.
Phototherapy and patch testing: payer-specific medical-necessity gating
Phototherapy fragments into UV light (CPT 96900), PUVA (96910), and UVB (96912), each with payer-specific diagnosis requirements. BCBS plans typically require ICD-10 codes in the L40.x (psoriasis), L20.x (atopic dermatitis), or L80 (vitiligo) ranges paired with documentation of failed topical therapy. Patch testing under CPT 95044 is billed per patch, with single sessions running up to ~80 units — Aetna and Cigna both flag patch-test claims above 60 units for records review. Aetna additionally denies 96900–96912 claims when the chief complaint codes to a cosmetic indication rather than a medical L-code diagnosis.
Dermatology-Specific Payer Issues We Watch For
UnitedHealthcare
Issue: Requires modifier XS instead of modifier 59 for distinct anatomic site biopsy unbundling, and denies claims using the older modifier
Our approach: We use modifier XS on all UHC claims for multiple biopsy sites and maintain documentation with specific anatomic site descriptions per their policy
Medicare
Issue: Bundles destruction codes (17000-17004) with biopsy codes when performed at the same anatomic site, even when clinical intent differs
Our approach: We ensure destruction and biopsy documentation describes distinct lesions at different anatomic sites and apply appropriate modifiers to unbundle when clinically supported
Aetna
Issue: Frequently denies phototherapy (96920-96922) claims as cosmetic without ICD-10 codes explicitly indicating medical necessity such as psoriasis or vitiligo
Our approach: We pair all phototherapy claims with the specific dermatologic condition ICD-10 codes and include chart notes documenting the medical indication and treatment protocol
BCBS
Issue: Limits Mohs surgery coverage to specific tumor types and anatomic locations, denying claims for Mohs performed on non-covered sites like the trunk
Our approach: We verify Mohs coverage criteria per BCBS plan before procedures and recommend alternative excision approaches when Mohs is not covered for the specific site and tumor type
What We Handle
Mohs surgery — region-coded stages, repair sequencing, and slide reconciliation
Coding for head/neck/hands/feet/genitalia (17311 + 17312) and trunk/extremities (17313 + 17314) Mohs cases, with same-day repair billing across 12001–13160 intermediate and complex closure ranges. Includes pathology slide-to-stage reconciliation per AAD and ASMS Mohs documentation standards.
Skin biopsies — the 11102–11107 technique family and add-on stacking
Technique-correct primary code selection across tangential (11102), punch (11104), and incisional (11106) biopsies, with proper add-on stacking (11103, 11105, 11107) and CPT 88305 dermatopathology coordination. Built around the 2019 CPT restructure that retired single-code 11100 billing.
Phototherapy — 96900/96910/96912 with payer-specific diagnosis pairing
Session billing for UV light (96900), PUVA (96910), and UVB (96912) paired with L40.x, L20.x, and L80 ICD-10 codes that satisfy BCBS, Aetna, and commercial medical-necessity criteria. Includes failed-topical-therapy documentation and treatment-frequency tracking.
Destruction and excision coding — 17000 series and 11400/11600 sizing rules
Destruction billing for premalignant lesions (17000 first, 17003 for 2–14, 17004 for 15+), with benign excision coding across 11400–11471 and malignant across 11600–11646. Lesion sizing in 0.5 cm increments to narrowest excision margin, body-region specific, with D23.x versus C44.x diagnosis discipline.
Biologic J-codes — Dupixent, Skyrizi, Cosentyx, Tremfya, and the buy-and-bill decision
J-code billing for Dupixent (J2796), Skyrizi (J2326), Cosentyx (J3245), and Tremfya (J1628), with NDC pass-through and average sales price reconciliation. Buy-and-bill versus specialty-pharmacy assignment-of-benefits routing per plan to prevent inventory exposure.
Teledermatology — 95 modifier, POS 02 vs 10, and store-and-forward billing
Teledermatology billing with the 95 modifier (replacing deprecated GT), POS 10 for patient-home and POS 02 for non-home telehealth, plus store-and-forward asynchronous reviews under payer-specific policy. Built around 2024 CMS rules and competing teledermatology payer pathways.
Key Dermatology CPT Codes
| CPT Code | Description | Avg. Reimbursement |
|---|---|---|
| 17311 | Mohs micrographic surgery, first stage, up to 5 tissue blocks | $710 |
| 17312 | Mohs micrographic surgery, each additional stage | $445 |
| 11102 | Tangential biopsy of skin, single lesion | $115 |
| 11104 | Punch biopsy of skin, single lesion | $125 |
| 17000 | Destruction of premalignant lesion, first lesion | $78 |
| 17003 | Destruction of premalignant lesion, 2-14 additional | $18 |
| 11600 | Excision of malignant lesion, trunk, arms, or legs, 0.5 cm or less | $215 |
| 96920 | Laser treatment for inflammatory skin disease | $185 |
Real Results
The Challenge
A 5-provider dermatology practice performing 800+ biopsies per month was losing revenue on same-day biopsy and destruction coding and had persistent issues with Mohs stage documentation mismatches
Our Approach
We audited biopsy and destruction bundling patterns, corrected modifier 59 usage for distinct anatomic site documentation, and implemented Mohs operative report reconciliation against billed stages and blocks
Key Outcomes
- check_circle Biopsy and destruction same-day revenue increased 26%
- check_circle Mohs billing accuracy improved from 89% to 99.1%
- check_circle Pathology specimen coordination errors eliminated
- check_circle Annual revenue increased by $187K across the practice
“We were eating biopsy revenue every single day because our modifier usage was inconsistent. MedPrecision fixed this in weeks, not months.”
Why General Billing Teams Miss Dermatology Issues
General billing staff handle dozens of specialties and rarely develop the depth needed for dermatology coding nuances. Here is what gets missed.
Modifier and bundling errors
Specialty-specific modifier rules and CCI edits are frequently overlooked by teams that do not work exclusively in dermatology.
Under-coding high-complexity visits
Dermatology encounters often qualify for higher-level E/M codes, but generalist billers default to mid-level codes to avoid audit risk.
Missed payer-specific rules
Each payer has unique coverage and documentation requirements for dermatology procedures that general teams rarely memorize.
Slow denial turnaround
Without specialty knowledge, appeal letters lack the clinical specificity needed to overturn dermatology denials quickly.
“The dermatology revenue leak that most practices overlook is not Mohs — it is the daily biopsy and destruction bundling that silently costs them $50,000 or more per year across a busy practice.”
MedPrecision Billing Team
Dermatology Coding Expert
Transition Plan
Switching billing partners should not disrupt patient care or cash flow. Our transition plan is designed for zero downtime.
Discovery and Specialty Audit
We review your current dermatology billing workflows, denial patterns, and payer mix to build a tailored onboarding plan.
System Integration
We connect to your EHR and practice management system, configure specialty-specific code sets, and validate charge capture workflows.
Parallel Billing Period
We run billing in parallel with your current process for 2-4 weeks to verify accuracy before taking over completely.
Full Transition and Reporting
Once validated, we assume full billing responsibility with monthly reporting dashboards and a dedicated account manager.
Dermatology Billing Terms
- Mohs Micrographic Surgery
- A specialized surgical technique for skin cancer removal where tissue is excised in stages and each stage is microscopically examined for cancer cells before proceeding. Billed per stage (17311 first, 17312 additional) and per tissue block (17314-17315).
- Modifier 59 / XS
- Modifiers used to indicate distinct procedural services performed at separate anatomic sites. In dermatology, essential for unbundling multiple biopsies or destruction procedures performed on different lesions during the same visit.
- Tangential Biopsy (Shave)
- A biopsy technique where a thin layer of tissue is removed using a horizontal cut. Coded as 11102 for the first lesion and 11103 for each additional. Different from punch biopsy in technique, coding, and reimbursement.
- Destruction of Premalignant Lesion
- Removal of precancerous growths (actinic keratoses) using cryotherapy, electrodesiccation, or chemical agents. The first lesion is coded with 17000 and each additional lesion (2-14) with 17003. Lesions beyond 14 use 17004.
- Complex Repair
- Wound closure requiring more than layered closure, such as scar revision, debridement, or extensive undermining. Billed separately from the Mohs excision using repair codes (13100-13153) based on anatomic site and length.
- Pathology Specimen Coordination
- The process of matching each biopsy or excision procedure code with its corresponding pathology specimen and interpretation code. Mismatches between procedure counts and specimen counts trigger audits.
Last updated: 2026-03-31
Common Questions
Common questions about dermatology billing services.
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Request Review arrow_forwardHow do you bill for Mohs surgery with multiple stages?
We bill the first stage using CPT 17311, each additional stage with 17312, and any tissue blocks beyond the first in each stage with 17314-17315. Closure and repair procedures are billed separately using appropriate repair codes. We ensure stage and block counts match the operative report exactly.
How do you handle cosmetic procedures that are also medically necessary?
When a procedure has both cosmetic and medical components, we bill the medically necessary portion to insurance with supporting documentation of the medical diagnosis and necessity. The cosmetic portion is billed to the patient separately. Clear documentation distinguishing the two is essential.
Can multiple biopsies be billed on the same day?
Yes. The first biopsy is billed with the primary code (11102-11107 based on technique), and additional biopsies at different sites use the corresponding add-on codes. Each biopsy must be documented at a distinct anatomic site with a separate pathology specimen.
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