Dermatology medical billing services
Lesion codes selected by millimetres, repairs that are separately billable but rarely billed, and a constant line between medical necessity and cosmetic exclusion.
Also called: Dermatologist · Skin Cancer · Mohs Surgery. We keep one page per specialty rather than a page per name.
Why dermatology billing is different
Dermatology codes are dimensional. An excision is selected by the lesion diameter plus the narrowest margins required, measured before excision — not by the size of the specimen after it shrinks in fixative. Practices that measure late, or measure the specimen, systematically code a size tier low across thousands of excisions a year. The clinical work is identical; the payment is not.
Destruction and biopsy codes are counted, not sized, and the counting rules differ. Premalignant destruction is billed as first lesion plus additional lesions in defined bands. Biopsies are billed as first lesion plus each additional, by technique — tangential, punch or incisional — and using one biopsy code for four lesions is one of the most common lost-revenue patterns in the specialty.
Repairs are the third piece. Simple repair is included in the excision. Intermediate and complex repair are separately payable, summed by length within the same anatomic grouping, and a great deal of that work is documented in the operative note and never reaches the claim.
Over all of it sits the cosmetic question. The same procedure on the same lesion is covered or excluded depending on documented symptoms, and the documentation has to exist before the claim, not after the denial.
Codes we work with
The families this specialty actually bills, and where each one carries a rule worth knowing.
| Family | Range | Notes |
|---|---|---|
| Skin biopsy | 11102–11107 | Tangential, punch and incisional, each with an additional-lesion add-on |
| Destruction, premalignant | 17000, 17003, 17004 | First lesion, second through fourteenth, then fifteen or more |
| Destruction, benign and malignant | 17110, 17111, 17260–17286 | Counted by number and, for malignant, by size and site |
| Excision, benign lesions | 11400–11471 | By site and by excised diameter including margins |
| Excision, malignant lesions | 11600–11646 | By site and by excised diameter including margins |
| Repairs | 12001–13153 | Simple, intermediate and complex, summed by length within a site group |
| Mohs micrographic surgery | 17311–17315 | By stage and by number of blocks |
| Pathology | 88304, 88305, 88312–88342 | Component split where read by an outside laboratory |
| Injections and biologics | J-codes, 96372, 96401 | Drug product and administration billed separately, with wastage rules |
Modifiers that matter
And the specific way each one is most often misused in this specialty.
| Modifier | Use | Common error |
|---|---|---|
| 25 | Separate E/M on the same day as a procedure | Omitted where a distinct evaluation occurred, so the visit is bundled away |
| 59 / XS | Distinct procedural service or separate site | Not applied on separate lesions at separate sites, producing duplicate denials |
| LT / RT | Laterality where the site is paired | Left off, so bilateral lesion work reads as a duplicate |
| 51 | Multiple procedures | Applied to add-on lesion codes that are exempt from the reduction |
| 58 / 78 / 79 | Staged or unrelated procedure in a global period | Missing on a planned re-excision after positive margins |
| JW / JZ | Drug amount discarded, or no amount discarded | Not reported, which is now a claim requirement for single-dose products |
Top denial reasons
With the CARC code you will see on the remittance, and what we do to stop each one recurring.
| Denial | CARC | How we prevent it |
|---|---|---|
| Service considered cosmetic and not covered | CO-96, CO-50 | Symptom and functional documentation captured before the procedure |
| Multiple lesions read as duplicate claims | CO-18 | Site and laterality modifiers applied per lesion |
| Procedure bundled into the same-day visit | CO-97 | Modifier 25 applied where distinct evaluation is documented |
| Lesion size or site not documented | CO-16 | Pre-excision measurement captured in the template as a required field |
| Biologic therapy not authorised | CO-197 | Authorisation and re-authorisation tracked per drug and per interval |
Prior authorisation in this specialty
Routine dermatologic surgery is not usually authorised in advance, but biologics are — and they dominate the authorisation workload in a modern dermatology practice. Systemic therapy for psoriasis, atopic dermatitis and hidradenitis typically requires documented step therapy, body surface area or severity scoring, and periodic re-authorisation. Phototherapy courses and some laser treatments carry their own criteria. We build the clinical package against the payer’s published criteria, track the authorised interval, and re-authorise before the course lapses.
Where revenue leaks
- Excisions sized from the specimen rather than the lesion plus margins, coding a tier low every time
- Additional-lesion biopsy and destruction add-on codes never billed
- Intermediate and complex repairs documented in the note and absent from the claim
- Drug wastage not reported on single-dose vials
What we do for dermatology practices
The parts of the cycle where this specialty gains the most, framed for how it actually bills.
Medical Coding
Certified CPC and CCS coders assign and validate ICD-10, CPT, and HCPCS codes from your documentation.
See medical codingMedical Billing & Coding Audits
Retrospective and pre-bill audits that find both compliance risk and missed revenue.
See billing & coding auditsPrior Authorization Services
Auth requests submitted, tracked, and escalated so procedures aren't delayed.
See prior authorizationDenial Management & Appeals
Root-cause analysis, corrected claims, and clinical appeals filed inside payer deadlines.
See denial managementSee what this specialty is losing in your practice
We run the analysis against dermatology benchmarks, not a generic template. Send 90 days of claims data and keep the report either way.
Questions about dermatology billing
How do you determine excision size?
From the lesion diameter plus the narrowest margins required, measured before excision — not from the specimen after fixation.
Do you bill repairs separately?
Yes, where the repair is intermediate or complex. Simple repair is included in the excision.
How do you handle cosmetic versus medical necessity?
The symptom and functional documentation is captured before the procedure, so coverage is settled in advance rather than argued after a CO-96 denial.
Can you manage biologic authorisations?
Yes, including step therapy documentation, severity scoring and re-authorisation before the approved course lapses.
Adjacent specialties
Specialties whose billing shares rules, payers or authorisation patterns with this one.