Where Dermatology Practices Lose Revenue: 9 Billing Mistakes and How to Fix Them

Dermatology has the highest modifier 25 rate of any specialty, at 61.5%, according to a November 2025 OIG audit. Most of these errors came from poor notes, wrong visit levels, and misuse of modifier 25. 

This shows that clinics don’t lose money because of a lack of patients. They lose it because of a few dermatology billing errors that keep repeating. In one visit, a doctor may do an exam, a biopsy, and a lesion removal. If the notes are weak or the modifier is wrong, many claims can get denied.

CMS has a helpful guide on how dermatologists can bill E/M services. In this blog, we explain where dermatology medical billing goes wrong and how to fix each problem.

What is Dermatology Billing & What Makes It So Complicated?

First of all, let’s understand that dermatology billing is the process of turning every skin-related service into accurate codes and claims that payers will actually pay. 

What makes it tricky is that a single visit can include an exam, biopsies, and lesion treatments, each with its own coding rules, modifiers, and documentation needs. Add the medical versus cosmetic divide, and errors happen easily.

Why Busy Dermatology Practices Still Experience Revenue Loss

Dermatology is a specialty with many procedures and high volume. One visit may consist of a skin exam, 3 biopsies, multiple skin lesions treated by cryotherapy, and a counseling discussion. Each of these has its own coding rules, payer edits, and documentation rules.

Revenue loss usually happens in three places:

• Before the claim: weak documentation, missing authorizations, and eligibility gaps.
• During coding: wrong procedure families, misused modifiers, and unlinked pathology results.
• After submission: slow denial follow-up, underpayments posted as paid, and aging claims nobody owns.

Most practices are only watching for collections, and they’re not going to catch these leaks, as the money is not going to disappear in a dramatic event. It’s worn down by the little write-offs, the unworked denials, and the still-too-young claims. The key to effective dermatology revenue cycle management is identifying these leaks at the source.

The 9 Billing Mistakes That Lead to Lost or Delayed Revenue

Incomplete Lesion and Procedure Documentation

Payers pay for what the chart supports. No details about where the lesions are, what they are, or why a procedure was performed immediately equals dermatology claim denials. The “Lesion removed from the arm” will not delay. A note such as “3 mm irregular pigmented lesion on left forearm; it has been changing in color; shave biopsy was performed” will.

Fix: Create EHR templates that mandate location, size, number of lesions, technique, and clinical purpose. Check a sample of charts weekly with billed codes.

Incorrect Biopsy, Destruction, and Excision Coding

These are among the common dermatology coding mistakes, and the differences matter. Biopsy codes (11102-11107) are based on the biopsy technique. Premalignant lesions are coded from 17000 to 17004, whereas benign lesions are coded 17110-17111, depending on the number of lesions. Excision codes (114xx for benign, 116xx for malignant) are based upon lesion diameter and margin, and sometimes the final pathology result.

Fix: Make it so that the coders match the procedure note to the code family, and wait for the final diameter and pathology to be confirmed before submitting claims. Retrain providers in lesion count thresholds.

Unsupported Modifier 25 or 59 Usage

Modifier 25 indicates that an E/M service was performed on the same day as a procedure and was significant and separately identifiable. The X-modifier (called modifier 59) indicates a separate procedure service. Both are examined by the payers. The problem with overuse is denial and audits, and underuse is letting good money go out the door.

Fix: When the note contains work beyond a typical pre-procedure evaluation, it is appropriate to use modifier 25 only when a new problem or a new complaint is noted. Only use X-modifiers where lesions or sites are definitely separate, as indicated in the documentation. The E/M and minor procedure guidance provided by CMS is a good starting point for provider training.

Missing Pathology-to-Coding Follow-Up

When making a diagnosis, the pathology result is used to generate diagnosis codes, follow-up care, and in some cases, the next procedure, all of which create a loop. If results are not matched to the encounter, claims are sent with undiagnosed claims, or if an excision had been coded as benign and pathology determined malignancy, it is sent out with a benign diagnosis.

Fix: Maintain a specimen log that correlates each specimen to a patient, date, and lab. If a specimen test is not completed within a specific time, mark it as such, and change a diagnosis code prior to claim submission.

Medical Versus Cosmetic Coverage Confusion

Wart treatment, seborrheic keratosis removal, scar revision, and some injectable treatments can fall on either side of the medical-necessity line. Billing a payer for a service that they view as cosmetic is a denial, and not billing a patient without prior notice will result in complaints.

Fix: Scheduling requests for likely cosmetic services for screening. Record symptoms (pain, bleeding, irritation, inflammation) when medically necessary. When coverage is unlikely, use financial-responsibility forms; for Medicare patients, use an ABN form.

Prior Authorization Gaps

Authorizations are typically required for biologic therapies, phototherapy, Mohs surgery in some plans, and some advanced treatments. If a request for authorization is not received, it is generally denied, and “catch up” authorization is difficult.

Fix: Automated Payer-Specific Authorization Grid. Check requirements during scheduling, not at check-in, and document all requests until they are approved or denied.

Incorrect Contractual Payment Posting

Underpayments resemble normal adjustments when payments are made without a comparison to the contracted fee schedule. Only a practice can deduct thousands of dollars as “contractual adjustments,” which were never contractual.

Fix: Upload payers’ fee schedules to your billing software or use variance reports. Indicate with a flag any payment that is less than the Allowable.

Unresolved Claims in Aging A/R

Each payer has a time frame for filing and appealing. Claims in the buckets of 60, 90, and 120 days are typically the most easily lost. Typically, this is due to lack of follow-up.

Fix: Identify worklists to assign to A/R by payer, establish follow-up cadences for unpaid claims (such as every 14 days), and escalate claims coming up to the appeal deadline.

Failure to Track Repeat Denial Patterns

Fixing individual denials without tracking causes is a treadmill. If the same payer denies modifier 25 claims every month, the root cause is upstream, and working each denial one by one won’t fix it.

Fix: Categorize denials by reason code, payer, provider, and CPT code. Review the trends monthly and feed findings back to front desk, coding, and clinical teams. This is the core of how to reduce denials in dermatology.

What a Dermatology Billing Audit Should Examine

An audit should follow the claim from scheduling through final payment. A thorough review covers:

• Documentation-to-code match: Do the notes support the procedure, lesion count, and modifier billed?
• Modifier patterns: Which providers use 25 and 59 most, and how are those claims paying?
• Pathology reconciliation: Are all specimens tied to final diagnoses?
• Denial data: Top reasons, top payers, and appeal success rates.
• Payment accuracy: Allowed amounts versus contracted rates.
• A/R health: Aging distribution and timely filing risk.

Benchmarks help you judge results. These are commonly cited industry targets, and your own goals may differ by payer mix:

If your numbers sit well outside these ranges, preventable leakage is likely.

A 30-Day Plan to Identify Preventable Revenue Leakage

You don’t need a six-month project to find where money is leaking. A focused month is enough.

Start with appeals on claims still inside the filing window. These typically give the fastest return and fund the rest of the cleanup.

When Should a Dermatology Practice Consider Outsourcing Billing?

Outsourcing billing is the only option left when all your reimbursement has gone down. Revenue Leakage should be stopped as soon as possible. If your dermatology practice is struggling with high denial rates or aging A/R, you don’t have to fix it alone. Contact our dermatology billing specialists today for a complimentary revenue cycle assessment and find out where your clinic is leaving money on the table. In-house billing works until volume, payer complexity, or staff turnover outgrows it. Consider outsourcing when:

• Denial rates stay high despite internal efforts.
• A/R keeps aging, and follow-up is inconsistent.
• Billers lack dermatology-specific coding expertise.
• Providers are spending time on billing questions instead of patients.
• You’re expanding locations or adding procedures like Mohs or cosmetic services.

When evaluating a dermatology medical billing company, ask about specialty experience, modifier and pathology workflows, denial management and reporting, and transparency in fees and performance metrics. Good dermatology medical billing services should give you regular reports, not just a monthly deposit. They should also work as an extension of your front office, helping with authorizations, eligibility, and coding questions.

Final thought

Revenue loss in dermatology is rarely caused by one big failure. It comes from small, repeated gaps across documentation, coding, authorization, and follow-up. Close those nine gaps, monitor your indicators every month, and your practice can recover the money it has already made.

Frequently Asked Questions 

Why do dermatology claims get denied?

Common issues are missing or inadequate documentation, improperly used modifiers, failure to obtain prior authorization, cosmetic vs. medical service coverage disputes, and eligibility issues. Understanding why dermatology claims get denied at the payer level helps you fix causes rather than symptoms.

How much revenue do dermatology practices lose to billing errors?

There is no single figure. These estimates are subject to payer mix, size, and workflow quality. In the industry, it is often claimed that losses are in the single digits to low double digits as a percentage of potential revenue. The only way to know the amount of revenue your dermatology practice has lost is to audit your own claims, denials, and A/R. Auditing your own claims, denials, and A/R is the only reliable way to measure your dermatology practice revenue loss.

What is the most common dermatology billing error?

The use of modifiers out of sequence (25 on an E/M visit along with procedure codes) and documentation issues that do not support the code(s) billed are two of the most common. The education and coding review of providers can prevent both of them. 

When can you bill modifier 25 with a biopsy?

Modifier 25 can be appended to an E/M service when a patient’s problem needed a more extensive, separately identifiable evaluation beyond the typical pre-procedure evaluation. For instance, the patient presented with a new rash and had a suspicious lesion biopsied. The E/M work must be clearly identified on the note. There are a variety of different Payer policies, so it’s important to consult each Payer’s rules.

Should a dermatology practice outsource billing?

It depends on your volume, denial rate, your knowledge, and your future plans. When your clean claim rate is poor, A/R is “aging,” and staff has trouble keeping up, outsourcing to a partner with a specialty focus can help improve cash flow and free up your staff to spend more time with patients.

Resources:
OIG Audit: Dermatology Providers Generally Met Medicare Requirements for E/M Services Performed on Same Day as Minor Surgical Procedures (November 2025)
https://oig.hhs.gov/reports/all/2025/dermatology-providers-generally-met-medicare-requirements-for-evaluation-and-management-services-performed-on-same-day-as-minor-surgical-procedures/
CMS Evaluation and Management Services Guide (MLN006764)
https://www.cms.gov/files/document/mln006764-evaluation-management-services.pdf
AAD: OIG Report Supports Dermatologists’ Use of Modifier 25
https://www.aad.org/member/publications/impact/2026-issue-1/dermatologist-use-of-modifier-25