Carbon-dioxide (CO2) laser resurfacing is the most aggressive skin-rejuvenation treatment in common use. A fully ablative CO2 laser vaporizes the entire surface layer of the skin in a single pass; a fractional CO2 laser does the same in microscopic columns, leaving untreated skin between them to speed healing. Both produce some of the strongest results available for deep wrinkles, acne scarring, and sun damage — and both carry the highest complication rate of any resurfacing modality. The trade-off is built in: the deeper the injury, the more dramatic the remodeling, and the wider the door for infection, pigment change, and scarring.
The short version for patients is that CO2 resurfacing is safe and effective in the right hands, on the right patient, with the right aftercare — and unforgiving otherwise. Three complications dominate the clinical literature: infection (bacterial, fungal, and especially herpes simplex reactivation), pigment change (post-inflammatory hyperpigmentation in darker skin, and delayed hypopigmentation that can be permanent), and scarring (hypertrophic scars and, around the eyes, ectropion). Public device-event reports add a fourth, less clinical layer: device malfunctions and energy-delivery problems, which have risen steadily in U.S. data since 2023.
This article lays out what the FDA's public device-event database shows for resurfacing lasers, what the published complication rates are, and what an informed-consent discussion for CO2 resurfacing should actually cover. It is educational and is not a substitute for an individualized consultation with a qualified clinician.
Why CO2 resurfacing causes the complications it does
A CO2 laser emits a 10,600 nm wavelength that water in the skin absorbs strongly. Because skin is mostly water, each pulse instantly heats tissue to vaporization, removing a controlled layer. The depth is set by the energy (fluence), the number of passes, and — for fractional devices — the density of microscopic treatment zones. Heat also spreads beyond the vaporized column into surrounding dermis, which is what triggers collagen remodeling (the benefit) but also thermal injury (the risk).
This creates a large open wound and a prolonged healing phase. Fully ablative CO2 leaves raw skin that takes roughly two weeks to re-epithelialize and stays pink for weeks to months afterward. During that window the barrier is broken: bacteria, yeast, and viruses can colonize the resurfaced skin, melanocytes can be triggered into overdrive (hyperpigmentation) or destroyed (hypopigmentation), and any area heated too aggressively can heal with thickened, raised scarring. The erbium:YAG (Er:YAG) laser, which absorbs water even more efficiently and produces less surrounding heat, trades some collagen tightening for a lower complication rate and is often preferred for lighter resurfacing and for patients at higher pigment risk.
What public device-event reports show
The FDA's MAUDE database collects adverse-event reports for medical devices. An analysis of public MAUDE records for the FDA product codes covering resurfacing lasers — the general "powered laser surgical instrument" code (GEX), filtered to ablative CO2 and resurfacing brands (Lumenis UltraPulse and AcuPulse, Cynosure, DEKA SmartXide, and similar), plus the dedicated fractional microbeam laser code (ONG) — found the breakdown below (extract dated 2026-06-10).
| Laser category | Reports |
|---|---|
| Ablative CO2 / ablative resurfacing brands (GEX) | 799 |
| Fractional microbeam lasers — Fraxel, Clear + Brilliant (ONG) | 107 |
| Combined resurfacing-laser reports | ~906 |
Among the ablative CO2 reports, roughly 419 are recorded as patient injuries and 332 as device malfunctions. The fractional-laser reports skew heavily toward injuries. The manufacturer landscape is concentrated: Lumenis dominates (its UltraPulse and AcuPulse families account for the largest share), followed by Cynosure and DEKA. And the trend is upward — combined resurfacing-laser reports rose from 82 in 2023 to 91 in 2024 and 106 in 2025, with a further 45 already logged in the partial 2026 extract.
Two important cautions on this data. First, MAUDE is passive and voluntary, so the trend partly reflects rising treatment volume and reporting behavior rather than a clean risk increase. Second, the general surgical-laser code (GEX) is a catch-all: it captures cosmetic facial resurfacing devices alongside CO2 lasers used for other surgical purposes, so the raw count overstates resurfacing-specific events and should not be read as a patient-level complication rate. The value of the data is in the manufacturer concentration and the rising trend, not in a precise denominator.
The complication rates the clinical literature reports
Where device data is noisy, clinical studies are specific. The published rates for the complications patients actually care about are well characterized:
| Complication | Reported rate (ablative / fractional CO2) |
|---|---|
| Herpes simplex virus (HSV) reactivation | ~2–7% traditional ablative; ~1% fractional (with prophylaxis, lower) |
| Bacterial infection | ~0.5–4.5% (Staph. aureus, Pseudomonas, Enterobacter) |
| Prolonged erythema (redness) | >12.5% ablative (resolves ~3 months); <1% non-ablative |
| Acneiform eruption / milia | up to ~80% / ~14% in non-fractionated resurfacing |
| Post-inflammatory hyperpigmentation (PIH) | common, peaks ~3–8 weeks; highest in Fitzpatrick IV–VI |
| Hypopigmentation | delayed onset; can be permanent (line of demarcation) |
| Hypertrophic scarring / ectropion | rare; the most severe resurfacing complications |
A few of these deserve explanation:
- Herpes reactivation is the most common infection, and it is largely preventable. Resurfacing the perioral skin can reactivate the cold-sore virus even in patients with no recent history, and a disseminated outbreak can scar. Standard practice is antiviral prophylaxis (such as valacyclovir) starting before treatment and continuing through re-epithelialization. With prophylaxis, reactivation in fractional CO2 series has been reported at roughly 1%.
- Bacterial infection is the gateway to scarring. Rates are low with sterile technique and post-procedure care, but a missed superficial infection — often in the first post-treatment week — can progress to a deeper infection and permanent scarring. Vigilant wound checks and, when indicated, prophylactic antibiotics are the countermeasure.
- PIH is the signature skin-of-color risk. Hyperpigmentation is "possibly the most common complication in darker skin types" after laser resurfacing, and CO2 — the most aggressive modality — is the highest-risk choice. Conservative energy, lower treatment density, pre- and post-treatment skin conditioning (often with hydroquinone or retinoid regimens), and strict sun protection are used to manage it. In Fitzpatrick V–VI, fully ablative CO2 is often avoided in favor of fractional, Er:YAG, or non-ablative options.
- Hypopigmentation is the sleeper complication. Unlike PIH, which usually fades, laser-induced lightening can appear months later and be permanent — a tell-tale line of demarcation at the jawline when only the face is treated. It reflects loss of melanocytes from thermal injury and is the reason some clinicians extend treatment past the jawline or favor less aggressive settings.
- Smoking materially raises the risk. Nicotine impairs wound healing; the standard informed-consent discussion flags current smokers and nicotine users as at greater risk of skin loss, delayed healing, and additional scarring.
What informed consent for CO2 resurfacing should cover
Because CO2 resurfacing is genuinely ablative surgery of the skin, a thorough consent discussion is not a formality — it is the map of what can go wrong. Based on standard plastic-surgery consent documents and the clinical literature, a complete discussion names:
- Infection — bacterial, fungal, and viral (HSV), the role of antiviral and sometimes antibiotic prophylaxis, and the fact that disseminated infection can scar and, in extreme cases, cause serious illness.
- Burns — laser energy can burn; severe burns scar.
- Pigment change — both hyperpigmentation (transient to prolonged, worse in darker skin) and hypopigmentation (potentially permanent).
- Scarring — hypertrophic scarring and, near the eyes, ectropion (a pulled-down lower eyelid).
- Eye injury — the laser can damage the eye; protective eyewear is non-negotiable.
- Prolonged redness and texture change — weeks to months of erythema are expected, not abnormal.
- Smoking and wound healing — the added risk for tobacco and nicotine users.
The scarring literature for fractional CO2 is consistent on cause: scars tend to follow overly aggressive treatments in sensitive areas (eyelids, neck, and especially the lower neck and chest), excessive energy or density, uncontrolled infection, or placement in skin not suited to the depth used. Sensitive areas warrant lower energy and density — and a provider who can articulate that is reading from the textbook.
Recovery, and what turns a side effect into a scar
Two practical points the clinical literature and standard patient instructions emphasize:
- The timeline is long, and knowing that prevents its own problems. Fully ablative CO2 leaves raw skin for roughly two weeks; fractional CO2 about a week; Er:YAG about a week. Redness is expected, not abnormal, and can persist for two to three months — sometimes up to a year, often longer in fair, blonde, or red-haired patients. A patient who understands this keeps up the sun protection that prevents PIH during the pink phase rather than stopping it once the skin looks healed.
- Most permanent scarring traces back to disruption of healing skin. The classic benchmark for the CO2 complication profile is a 1998 review of roughly 1,000 resurfacing procedures (Nanni and Alster); in practice the preventable causes of scarring are picking or scratching crusting skin, an uncontrolled infection in the first week, and over-aggressive settings in sensitive areas (eyelids, neck, chest). Treat the resurfaced skin as an open wound: keep it moist with the recommended ointment, don't pick crusts, and report spreading redness, new pain, or drainage promptly.
What to ask before a CO2 resurfacing treatment
- Is fully ablative CO2 the right depth for my goal and my skin, or would fractional CO2 or Er:YAG achieve most of the result with less downtime and pigment risk? The most aggressive option is not always the best first choice.
- Given my Fitzpatrick type, what is my realistic PIH and hypopigmentation risk, and how do you manage it? A specific answer about pre-treatment conditioning, conservative settings, and sun protection matters; for Fitzpatrick V–VI, CO2 may be the wrong tool.
- What infection prophylaxis do you use? Antiviral coverage through re-epithelialization should be routine; clarity on antibiotics and wound checks is a good sign.
- What does my aftercare look like, and how will you monitor me in the first two weeks? Close early follow-up is how a superficial infection is caught before it scars.
- Will you treat past my jawline, and how do you avoid a line of demarcation? This addresses the permanent-hypopigmentation risk directly.
- What is the plan if I develop prolonged redness, pigment change, or scarring? A provider with a real answer (topicals, lighteners, steroid injections, time) has managed complications before.
CO2 resurfacing earns its place in aesthetic medicine because nothing else matches it for deep wrinkles and scarring. Its complication profile is the price of that power, and it is well understood — which is exactly why skin-type selection, antiviral prophylaxis, conservative settings in sensitive areas, and close aftercare are not optional. They are what separates a strong result from a preventable injury.
Limitations
The MAUDE device-event figures describe a passive, voluntary reporting system and a catch-all surgical-laser code that blends cosmetic resurfacing with other CO2 laser uses; the counts are not a patient-level complication rate and the upward trend partly reflects rising treatment volume. The clinical complication rates cited (HSV, infection, erythema, PIH, scarring) are drawn from specific study populations, devices, and protocols, and they vary widely with operator skill, settings, depth, and aftercare. The single most important determinant of outcome is the provider; nothing here replaces an individualized assessment by a qualified clinician who can evaluate your skin in person.
Sources
- U.S. FDA, MAUDE (Manufacturer and User Facility Device Experience) database — analysis of adverse-event reports for ablative CO2/resurfacing lasers (product code GEX, brand-filtered) and fractional microbeam lasers (product code ONG), extract dated 2026-06-10: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/
- Complications and Legal Considerations of Laser and Light Treatments (HSV reactivation ~1–2% fractional CO2; hyperpigmentation most common in darker skin; up to 45% in skin types IV–VI): https://plasticsurgerykey.com/complications-and-legal-considerations-of-laser-and-light-treatments
- Complications in Lasers, Lights, and Radiofrequency Devices (prolonged erythema >12.5% ablative vs <1% non-ablative; bacterial infection 0.5–4.5%; HSV 2–7% traditional resurfacing; milia and acneiform rates): https://marmurmedical.com/wp-content/uploads/2021/02/Complications-in-Lasers-Lights-and-Radiofrequency-Devices.pdf
- Cosmetic Considerations in Dark-Skinned Patients — PMC (PIH common after ablative CO2; lower energy, density, and cooling in skin of color; fractional and Er:YAG lower complication rates than conventional ablative): https://pmc.ncbi.nlm.nih.gov/articles/PMC10844008
- Avram DK et al., "Complications of Fractional CO2 Laser Resurfacing: Four Cases" — Lasers in Surgery and Medicine (scarring from overly aggressive treatment in sensitive areas; eyelids, neck, chest): https://www.ovid.com/journals/lsam/fulltext/10.1002/lsm.20753~complications-of-fractional-co2-laser-resurfacing-four-cases
- Nanni CA, Alster TS. "Complications of carbon dioxide laser resurfacing: An analysis of 1,000 procedures." Plastic and Reconstructive Surgery 1998;101(4):1045–1050 (classic benchmark for the CO2 complication profile cited in standard reference texts).
- American Society of Plastic Surgeons model informed consent, Laser Resurfacing Procedures of Skin (infection, HSV, burns, pigment change, scarring, eye injury, smoking risk): https://drrohrich.com/downloads/forms/Laser_Resurfacing_Procedures_of_Skin.pdf
- Informed Consent for CO2 Laser Skin Resurfacing (hypopigmentation permanent; hyperpigmentation 3–8 weeks post; increased sun susceptibility): https://cockerhammd.com/wp-content/uploads/2024/06/Informed-Consent-for-CO2-Laser-Skin-Resurfacing.pdf
