CO₂ Laser – Dr Romano Geneva

Is continuous CO₂ laser still used ?

CO₂ laser was one of the first lasers used in dermatology and skin surgery. From the 1980s, it became an alternative to mechanical abrasion techniques, allowing highly precise tissue vaporisation or incision.
At that time, it was mainly used for warts, condylomas, certain benign skin lesions and tattoo removal. The laser then operated in continuous mode, an effective technology associated with a greater risk of scarring and sometimes substantial after-effects.
The arrival of pulsed lasers in the mid-1990s gradually replaced continuous CO₂ laser for many indications, particularly tattoo removal. A few years later, scanning systems enabled the development of the first skin resurfacing treatments for rejuvenation and scar management.
These early treatments were very effective but also very aggressive. Recovery was lengthy and the complication risk higher, particularly when indications or settings were not fully mastered.
A major advance occurred in the 2000s with the development of fractional CO₂ laser. By treating only a fraction of the skin surface at each session, this technology considerably improved the balance between effectiveness, safety and recovery time.
Today, continuous CO₂ laser retains specific indications, mainly in dermatological surgery. In aesthetic medicine, fractional technologies have become the reference for skin resurfacing and treatment of wrinkles, scars and photoageing.

How does CO₂ laser work ?

CO₂ laser emits light at a wavelength of 10 600 nm, which is strongly absorbed by water in the tissues. This property allows precise targeting of superficial skin layers.
The delivered energy is immediately converted into heat, causing controlled tissue vaporisation and stimulating natural skin repair mechanisms. In the weeks and months after treatment, fibroblasts produce new collagen fibres, gradually improving skin quality, firmness and texture.

What is the difference between
continuous CO₂ laser and fractional CO₂ laser
?

Continuous CO₂ laser treats the entire skin surface. Highly effective, it is also more aggressive, with longer healing time and a higher risk of side effects. Today, its use is mainly reserved for specific indications in dermatological surgery.
Fractional CO₂ laser works differently. Rather than treating the whole skin surface, it creates thousands of microscopic ablation zones separated by intact skin. These untreated areas accelerate healing, reduce recovery time and improve treatment tolerability.

What is the difference between
fractional CO₂ laser and Erbium laser ?

Fractional CO₂ laser acts more deeply and stimulates collagen synthesis more intensely. It is particularly indicated for pronounced wrinkles, acne scars and photoageing.
Erbium laser acts more superficially, although an experienced doctor can use it for deeper treatment with fewer side effects than CO₂. It enables gentler skin renewal, generally with milder after-effects and shorter recovery.
The choice between these technologies depends on skin quality, indications and the desired outcome.

What are the indications for combined methods ?

In certain situations, combining continuous CO₂ laser with fractional CO₂ laser or other technologies improves results. These protocols are reserved for specific indications and adapted individually.

Upper lip barcode lines

Vertical upper lip wrinkles, also called “barcode lines”, are among the most frequent indications for combined methods. Combining different techniques provides more even resurfacing alongside stimulation of collagen production.

Cosmetic tattoo

Cosmetic lip or eyebrow tattoos containing certain pigments can react unpredictably to pigment-targeting lasers. In some situations, CO₂ laser can be used as part of specific care to improve pigment removal.

Rhinophyma

Rhinophyma, characteristic of stage IV rosacea, is a progressive thickening of nasal skin that can benefit from CO₂ laser treatment. Depending on lesion severity, combining different laser modes allows precise tissue reshaping.

Aesthetically troublesome dermatological conditions

Continuous CO₂ laser also retains a role in functional or aesthetic treatment of certain benign skin lesions, including xanthelasma, syringomas, keloids, certain neurofibromas, foreign-body granulomas or ingrown toenails.

Contraindications to CO₂ laser in
continuous mode

Continuous CO₂ laser treatment cannot be performed in certain situations.
It is contraindicated in cases of :

Pregnancy or breastfeeding.
Active skin infection in the treatment area (herpes, impetigo, a wound or any other local infection).
A recent tan or significant sun exposure in the weeks before treatment.
An active inflammatory skin disease in the treatment area.

Particular care is also needed in patients :

With phototypes IV to VI, due to a higher risk of post-inflammatory hyperpigmentation.
With a history of hypertrophic scars or keloids.
Receiving photosensitising treatment.
With a healing disorder or a condition that may slow skin repair.

Precautions before the session

Several precautions are needed before continuous CO₂ laser to ensure a safe session and promote good healing :

Have a preliminary medical consultation to confirm that continuous CO₂ laser is indicated.
Check for possible contraindications, including active skin infection, an evolving herpes outbreak, inflammatory skin disease or a recent tan.
Avoid significant sun exposure, including tanning beds, during the 2 to 4 weeks before the session.
Ensure the skin is not tanned on treatment day to limit the risk of skin reactions or pigmentation changes.
Report any history of herpes, particularly when treatment involves the face or mouth area.
If necessary, take preventive antiviral treatment prescribed by the doctor according to the treated area and the patient's history.
Avoid chemical peels, microneedling, dermabrasion and any irritating treatment on the area during the 4 weeks before the session.
Stop topical retinoids (retinol, tretinoin, adapalene, tazarotene) approximately one week before treatment, following the doctor's advice.
Do not apply potentially irritating products in the days before the session, particularly exfoliating acids (AHA, BHA), scrubs or products with high concentrations of vitamin C.

Precautions after the session

Aftercare following continuous CO₂ laser is essential for good healing and limiting complications.

Apply a repair cream until healing is complete.
Gently cleanse the treated area once or twice daily with a mild cleanser, without rubbing.
Keep the skin well hydrated to promote healing and limit discomfort.
Do not remove crusts, even if they become bothersome. They fall off naturally during healing.
Avoid make-up on the treated area until fully healed or as advised by the doctor.
Do not use scrubs, peels, exfoliating acids (AHA, BHA), retinol, tretinoin or other potentially irritating products for one month.
Avoid all direct sun exposure until fully healed, then apply SPF 50+ sun protection daily for at least 2 to 3 months to limit post-inflammatory hyperpigmentation.
Avoid tanning beds for 3 months.
Attend follow-up appointments to monitor healing and assess treatment results.

After-effects

Recovery depends on treatment depth, the surface treated and the indication.
In the hours after the session, redness and moderate swelling in the treated area, along with warmth or mild burning, are usual.
Temporary oozing followed by crust formation is expected over the following days. These reactions are part of normal healing.
In most cases, re-epithelialisation occurs within 7 to 10 days. Residual redness may persist for several weeks or longer depending on the settings used.

Side effects

Continuous CO₂ laser can cause side effects. Most are temporary and gradually subside during healing. The complication risk remains low when treatment is performed by an experienced doctor and recommendations before and after the session are followed.
The most frequent adverse effects are :

Persistent redness.
Swelling of the treated area.
Crusts during healing.
Skin sensitivity or a sensation of heat.

More rarely, observed complications include :

Post-inflammatory pigmentation or hypopigmentation.
A skin infection.
Reactivation of herpes.
Delayed healing.
A hypertrophic scar (exceptional).

Results

Results depend primarily on the indication treated. Continuous CO₂ laser removes or reshapes tissue with very high precision.
Depending on the indication, treatment can notably :

Remove certain benign skin lesions.
Correct rhinophyma.
Improve the appearance of certain scars.
Treat certain cosmetic tattoos.
Provide skin resurfacing within specific protocols.

After aesthetic treatment, improvement continues for several weeks through gradual collagen remodelling. The final result is generally assessed between 3 and 6 months after the session.

Why is a consultation essential ?

Every indication requires a preliminary medical assessment. The consultation confirms the diagnosis, checks possible contraindications, explains treatment benefits and limitations and defines the most appropriate therapeutic strategy.
When several techniques are possible, the choice depends on skin characteristics, lesion location and the desired result.

Continuous CO₂ laser prices

The price of continuous CO₂ laser treatment is quoted individually because it depends on the indication, treatment surface, intervention depth and type of anaesthesia required.
A session starts from 800 CHF.
A personalised quotation is provided during the medical consultation.

WHAT THE STUDIES SAY

A retrospective study assessed CO₂ laser treatment of rhinophyma in 124 patients. Continuous mode was particularly used to reduce excess tissue and reshape nasal contours, sometimes combined with a scanner. Treatment was performed in one session in 115 patients; at three months, outcomes were judged good to excellent in 118 patients. Questionnaire follow-up found high satisfaction, but only 52 people responded. These results concern rhinophyma and cannot be extrapolated to every laser indication.

Source: Madan et al., British Journal of Dermatology, 2009.

A comparative study involving 33 patients assessed the effectiveness of pulsed CO₂ laser and continuous CO₂ laser with a scanner for reducing facial wrinkles. Twenty-eight patients received one of the two treatments, while the other five had a comparison of both techniques on different facial areas. Reduced wrinkles were observed in all participants. Biopsies after treatment also revealed changes consistent with new collagen formation. These results remain limited by the small number of participants and concern only the technologies and parameters studied.

Source: Ross et al., Journal of the American Academy of Dermatology, 1997.

A study involving 102 women assessed the effectiveness of treatment combining an ablative Erbium:YAG laser and subablative continuous CO₂ laser for facial resurfacing, particularly around the eyes and mouth. Results were judged very good by 67 participants and good by another 25. Biopsies performed two months after treatment also showed new collagen formation. These results concern the combination of both lasers and cannot determine the effectiveness of continuous CO₂ laser alone. The absence of a control group also limits this study’s conclusions.

Source: Trelles et al., British Journal of Dermatology, 2002.

Frequently asked questions about continuous CO₂ laser

Is continuous CO₂ laser still used today ?

Yes. Although fractional CO₂ laser has become the reference in aesthetic medicine, continuous CO₂ laser retains specific indications, particularly for certain benign skin lesions, rhinophyma or combined protocols.

What is the difference between continuous CO₂ laser and fractional CO₂ laser ?

Continuous CO₂ laser treats the entire targeted surface, while fractional CO₂ laser creates multiple microscopic treatment zones separated by healthy skin. Fractional technology reduces recovery time while maintaining excellent effectiveness.

Is treatment painful ?

Comfort depends on the indication and extent of the treated area. Depending on the case, an anaesthetic cream, local anaesthesia or, more rarely, general anaesthesia may be needed.

How long does healing take ?

Healing time varies with the indication and treatment depth. A light treatment generally requires a few days of recovery, while more extensive treatment may need several weeks for complete healing.

Are the results permanent ?

When a lesion is fully treated, results are generally lasting. However, skin ageing continues naturally over time, which may warrant other treatments depending on the indication.