Ablative Fractional Lasers

The charts below show the chances of developing various side effects from laser resurfacing.^1-13 For some side effects, we currently do not have enough data to provide a percentage.

Certain/Likely Side Effects (% = Incidence)

Possible/Rare Side Effects

*Prolonged crusting: Prolonged crusting is crusting that lasts longer than 7 days.

Studies:

Thirteen studies have looked at the side effects of treatment with ablative fractional lasers.

• Study 1:
  
  
  • Authors: Ahmed et al.¹
  • Total # of patients: 14
  • # of female patients: (not reported)
  • # of male patients: (not reported)
  • Age of patients: Average: 22.7
  • Laser type: CO₂ fractional laser
  • Laser settings: 0.12 mm spot size, 0.9 W, 1.9 ms pulse duration, 99 Hz
  • Duration of treatment and follow-up: 4 treatments, follow-up for 3 months
  • Side effects:
    
    • Temporary hyperpigmentation (skin darkening): 14.2%
    • Infection: 14.2%
    • No complications: 35.7%
• Study 2:
  
  
  • Authors: Bjorn et al.²
  • Total # of patients: 13
  • # of female patients: (not reported)
  • # of male patients: (not reported)
  • Age of patients: 18-60
  • Laser type: CO₂ fractional laser
  • Laser settings: Deep FX handpiece: 17.5–22.5mJ/pulse, 70–90W, 0.25 ms pulse duration, density 3 (15% coverage) and Active FX handpiece: 100mJ/pulse, >125W, <0.8 ms pulse duration, density 3 (82% coverage)
  • Duration of treatment and follow-up:
    
    • 4 treatments, follow-up for 3 months
      
      • Side effects:
      • Mild to moderate erythema (redness): 63.6%
      • Mild hypopigmentation (skin lightening): 18.2%
      • Mild post-inflammatory hyperpigmentation (skin darkening): 45.5%
    • 2 treatmetns at 3-month intervals, follow-up at 1 and 6 months
      
      • Side effects:
        
        • Mild to moderate erythema (redness): 45.5%
        • Mild hypopigmentation (skin lightening): 27.3%
        • Mild post-inflammatory hyperpigmentation (skin darkening): 45.5%
• Study 3:
  
  
  • Authors: Cho et al.³
  • Total # of patients: 20
  • # of female patients: 13
  • # of male patients: 7
  • Age of patients: 19-33 Average: 27
  • Laser type: CO₂ fractional laser
  • Laser settings: Deep FX mode: 10-20 mJ, density 2, 300 Hz and Active FX mode: 50-100 mJ, density 2, <1 ms pulse duration, 75 Hz
  • Duration of treatment and follow-up: 1 treatment, follow-up at 3 months
  • Side effects:
    
    • Crusting or scaling: 100% (average: 6.3 days)
    • Erythema (redness): 100% (average: 2.8 days)
    • Limitations in activity: 100% (4.9 days)
    • Edema (swelling): 25%
    • Bleeding: 10%
    • Wound exudate (oozing): 15%
    • Post-therapy hyperpigmentation (skin darkening): 5%
    • Aggravation of inflammatory acne: 15%
• Study 4:
  
  
  • Authors: Hedelund et al.⁴
  • Total # of patients: 13
  • # of female patients: 7
  • # of male patients: 6
  • Age of patients: 22-54 Average: 33
  • Laser type: CO₂ fractional laser
  • Laser settings: 0.5 mm spot diameter, 12-14 W, 48-56 mJ/pulse, 100 MTZ/cm², density 13%, 4 ms pulse duration
  • Duration of treatment and follow-up: 3 treatments, follow-up at 2-3 days and 1, 3, and 6 months
  • Side effects:
    
    • Mild to moderate erythema (redness): 69.2%
    • Mild to moderate wounds: 100%
    • Post-inflammatory hyperpigmentation (skin darkening): 0%
• Study 5:
  
  
  • Authors: Majid and Imran⁵
  • Total # of patients: 60
  • # of female patients: 35
  • # of male patients: 25
  • Age of patients: 1 patient under age 20 and 1 patient over 40, the rest between 20 and 40
  • Laser type: CO₂ fractional laser
  • Laser settings: 15-25 J/cm², 100-150 MTZ/cm², 1.0-1.2 mm ablation depth
  • Duration of treatment and follow-up: 3-4 treatments, follow-up at 6 months
  • Side effects:
    
    • Transient acneiform (acne-like) lesions: 10%
    • Post-inflammatory hyperpigmentation (skin darkening): 5%
• Study 6:
  
  
  • Authors: Manuskiatti et al.⁶
  • Total # of patients: 13*
  • # of female patients: 8
  • # of male patients: 5
  • Age of patients: 25-52 Average: 34
  • Laser type: CO₂ fractional laser
  • Laser settings: 15 W, 49 MTZ/cm², 75-105 mJ/MTZ, 9.6% average coverage, 5-7 ms pulse duration
  • Duration of treatment and follow-up: 3 treatments, follow-up at 6 months
  • Side effects:
    
    • Post-inflammatory hyperpigmentation (skin darkening): 92.3%
    • Acneiform eruption (acne-like lesions): 30.8%
    • Allergic contact dermatitis: 15.4%
    • Herpes simplex infection (cold sores): 7.7%
• Study 7:
  
  
  • Authors: Manuskiatti et al.⁷
  • Total # of patients: 24*
  • # of female patients: 12
  • # of male patients: 8
  • Age of patients: 22-51 Average: 29.5
  • Laser type: CO₂ fractional laser
    
    • Laser settings: 12.5-15 mJ, 950 ls pulse duration
    • Duration of treatment and follow-up: 2 treatments, follow-up at 6 months
    • Side effects: Post-inflammatory hyperpigmentation (skin darkening): 50%
  • Laser type: Er:YAG fractional laser
    
    • Laser settings: 14 mJ, 350 ls pulse duration
    • Duration of treatment and follow-up: 2 treatments, follow-up at 6 months
    • Side effects: Post-inflammatory hyperpigmentation (skin darkening): 35%
• Study 8:
  
  
  • Authors: Wang et al.⁸Total # of patients: 5*# of female patients: 1# of male patients: 4Age of patients: 19-44 Average: 27Laser type: CO₂ fractional laserLaser settings: 300 µm spot size, 8 W, 28 J/cm², 2.5 pulse duration, 500 µm penetration depth, 20% skin coverage
  • Duration of treatment and follow-up: 2 treatments, follow-up at 8 weeks
  • Side effects: Post-treatment erythema (redness): 100%
• Study 9:
  
  
  • Authors: Yuan et al.⁹
  • Total # of patients: 20*
  • # of female patients: 10
  • # of male patients: 10
  • Age of patients: 22-31
  • Laser type: CO₂ fractional laser
  • Laser settings: Deep FX mode: 10 mJ or 20 mJ, 10% or 20% density
  • Duration of treatment and follow-up: 1 treatment, follow-up at 3 days, 1 week, 1 month, and 3 months
  • Side effects:
    
    • Cutaneous pruritus (skin itching): 40%
    • Skin dryness: 50%
• Study 10:
  
  
  • Authors: Zhang et al.¹⁰Total # of patients: 33*# of female patients: 14# of male patients: 19Age of patients: 19-34 Average: 26.4Laser type: CO₂ fractional laserLaser settings: Deep FX mode: 20-25 mJ, 10-20% coverage/cm² per pass, 300 Hz
  • Duration of treatment and follow-up: 3 treatments, follow-up at 5 months
  • Side effects: Post-inflammatory hyperpigmentation (skin darkening): 36.4%
• Study 11:
  
  
  • Authors: Nirmal et al.¹¹Total # of patients: 25# of female patients: 10# of male patients: 15Age of patients: 18-38Laser type: Er:YAG fractional laserLaser settings:
    
    • Session 1: 9 x 9 tip, 1,200 mJSession 2: 9 x 9 tip, 1,400 mJSession 3: 7 x 7 tip, 1,200 mJSession 4: 7 x 7 tip, 1,400 mJ. 2 Hz for all sessions
  • Duration of treatment and follow-up: 4 treatments, follow-up at 1 month
  • Side effects:
    
    • Exacerbation of acne lesions: 13%
    • Post-treatment hyperpigmentation (skin darkening): 2%
    • Prolonged crusting: 3%
    • Prolonged erythema (redness): 0%

* All patients were Asian

• Study 12:
  
  
  • Authors: Kim et al.¹²
  • Total # of patients: 23
  • # of female patients: 7
  • # of male patients: 16
  • Age of patients: 19-36
  • Laser type: CO₂ fractional laser
  • Laser settings: 100 mJ and a density of 100 spots/cm²
  • Duration of treatment and follow-up: 3 treatments, follow-up at week 12 and 20
  • Side effects:
    
    • Transient redness (erythema): (incidence not reported)
    • Swelling (edema): (incidence not reported)
    • Crusting: (incidence not reported)
• Study 13:
  
  
  • Authors: Bhat et al.¹³
  • Total # of patients: 104
  • # of female patients: 65
  • # of male patients: 39
  • Age of patients: 19-45
  • Laser type: CO₂ fractional laser
  • Laser settings: 20–30 mJ/MTZ; spot size 300 μm/ MTZ; handpiece 80 μm–50 mm; pulse width 0.04 ms; pulse repetition rate 10 kHz
  • Duration of treatment and follow-up: 4 treatments, follow-up for 6 months
  • Side effects:
    
    • Burning sensation/pain: 100%
    • Transient redness (erythema): 32%
    • Transient swelling (edema): 32%
    • Crusting and scaling: 32%
    • Delayed pigmentation: 12%

Study 1: In a study published in 2014 in the Journal of Cosmetic and Laser Therapy, Ahmed and colleagues treated 14 patients with icepick scars with CO₂ fractional laser. Patients received 4 treatments at 3-week intervals and were followed up for 3 months. The researchers advised the patients not to use any other scar treatment during the study. Over a third (35.7%) of the patients experienced no side effects.¹

Study 2: In a study published in 2014 in the journal Lasers in Surgery and Medicine, Bjorn and colleagues treated 13 patients with moderate to severe atrophic (indented) acne scars with CO2 fractional laser. Patients were given 2 treatments, which were administered at an interval of 1 month on one side of the face and at an interval of 3 months on the other side of the face. The researchers randomly assigned which side of the face received which treatment schedule. Side effects were mild and similar after both treatments.²

Study 3: In a study published in 2009 in the journal Dermatologic Surgery, Cho and colleagues treated 20 patients with mild to severe atrophic (indented) acne scars with 1 session of CO₂ fractional laser. Patients were followed up 3 months after treatment. All patients experienced mild side effects in the first 2-3 weeks after treatment. All patients experienced crusting or scaling which lasted for an average of 6 days. They also developed redness and couldn’t perform daily activities for an average of 5 days. Among less common side effects were swelling, bleeding, oozing, skin darkening, and aggravation of inflammatory acne.³

Study 4: In a study published in 2012 in Lasers in Surgery and Medicine, Hedelund and colleagues treated 13 patients with atrophic (indented) acne scars with CO₂ fractional laser. Patients were given 3 sessions of treatment at intervals of 4 to 5 weeks. Patients experienced mild side effects after each treatment. No patients developed post-inflammatory hyperpigmentation (skin darkening).⁴

Study 5: In a study published in 2014 in the Journal of Cutaneous and Aesthetic Surgery, Majid and Imran treated 60 patients with atrophic (indented) acne scars with CO₂ fractional laser. The patients received 3-4 sessions of treatment at 6-week intervals and were followed up 6 months after the last laser session. Most patients experienced erythema (redness) lasting 3-4 days and superficial crusting lasting 4-6 days, as well as mild transient edema (swelling). In addition, 6 patients developed acne-like lesions which, in two cases, had to be treated with oral medication. The only serious side effect was post-inflammatory hyperpigmentation (skin darkening), which occurred in 3 patients and disappeared over 2-3 months with the help of topical therapy.⁵

Study 6: In a study published in 2010 in the Journal of the American Academy of Dermatology, Manuskiatti and colleagues treated 13 Asian patients with atrophic (indented) acne scars with CO₂ fractional laser. The patients received 3 sessions of treatment at 7-week intervals and were followed up 6 months after treatment. The majority of patients experienced post-inflammatory hyperpigmentation (skin darkening), and many also developed acne-like lesions after treatment.⁶

Study 7: In a study published in 2013 in Dermatologic Surgery, Manuskiatti and colleagues treated 24 Asian patients with shallow or deep boxcar scars with fractional laser. The patients were randomly assigned to receive CO₂ fractional laser treatment on one side of the face and Er:YAG fractional laser treatment on the other side of the face. On each side, two laser treatments were administered at an interval of 2 months. The researchers followed up with the patients 6 months after the last treatment. Half of the patients developed post-inflammatory hyperpigmentation (skin darkening) on the side of the face treated with CO₂ laser, and 35% of the patients developed post-inflammatory hyperpigmentation on the side of the face treated with Er:YAG laser. Although CO2 laser treatment seemed to result in skin darkening more frequently, this difference was not statistically significant. In other words, the number of patients was too small for the researchers to definitively conclude that CO₂ laser treatment is more likely to cause skin darkening than Er:YAG laser treatment.⁷

Study 8: In a study published in 2010 in the Journal of Cosmetic and Laser Therapy, Wang and colleagues treated 5 Asian patients with moderate to severe acne scarring with CO₂ fractional laser. The patients received 2 treatment sessions at an interval of 6-8 weeks and were followed up 8 weeks after the second treatment. All patients experienced skin redness after the treatment which lasted 5-7 days. No other side effects occurred.⁸

Study 9: In a study published in 2014 in Dermatologic Surgery, Yuan and colleagues treated 20 Chinese patients with atrophic (indented) acne scars with CO₂ fractional laser. All patients received a single treatment with the laser, but the laser settings differed between patients. For instance, some patients were treated with the fluence set to 10 mJ on one side of the face and 20 mJ on the other side of the face. While the side effects were very similar on both sides of the face, they lasted slightly longer on the side of the face treated with the higher fluence. None of the patients experienced infection, scarring, acne flare-ups, or hypopigmentation (skin lightening) as a result of the treatment.⁹

Study 10: In a study published in 2013 in Dermatologic Surgery, Zhang and colleagues treated 33 Chinese patients with atrophic acne scars with CO₂ fractional laser on one side of the face. The patients received 3 treatments at intervals of 6-12 weeks (8 weeks on average) and were followed up 6 months after the last treatment. Over a third of patients developed post-inflammatory hyperpigmentation (skin darkening).¹⁰

Study 11: In a study published in 2013 in the Indian Journal of Dermatology, Venereology and Leprology, Nirmal and colleagues treated 25 patients with atrophic acne scars with Er:YAG fractional laser. The patients were given 4 treatment sessions at 1-month intervals and were followed up 1 month after the last treatment. Most patients experienced short-term redness, which lasted less than 2 days, and crusting, which lasted around 5 days. A few patients (3%) experienced prolonged crusting lasting more than 7 days, but none developed prolonged redness lasting over 4 days. The most common side effect was exacerbation of acne lesions, which was treated with oral antibiotics.¹¹

Study 12: In a study published in Yonsei Medical Journal in 2023, Kim and colleagues treated 23 patients with atrophic scars with CO₂ fractional laser. The patients were given 3 treatment sessions at 4-week intervals and were followed up 2 months after the last treatment. Most patients experienced short-term redness, swelling, and crusting, but the exact incidence of side effects was not reported.¹²

Study 13: In another study published in 2023 in Journal of Cutaneous and Aesthetic Surgery, Bhat and colleagues treated 104 patients with atrophic scars with CO₂ fractional laser. The patients were given 4 treatment sessions at 6-week intervals and were followed up for up to 6 months after the last treatment. All treated patients experienced short-term burning sensation or pain, while 32% of them reported redness, swelling, crusting, and scaling that lasted for 2 to 3 weeks. Moreover, 12% of patients reported delayed skin darkening (hyperpigmentation), which appeared 6 to 8 weeks after the treatment. Hyperpigmentation settled down after application of depigmenting creams.¹³