How does a pigment laser work?
Very short laser pulses shatter melanin clusters through heat and pressure effects. The body’s clearing cells then remove the fragments over time.
Q-switched lasers work in nanosecond pulses and picosecond lasers in even shorter ones. The shorter the pulse, the more the energy stays at the target before heat spreads, which can help protect surrounding tissue.
The spot may darken and crust shortly after treatment; the crust falls off within one to two weeks and the colour then lightens gradually. The crust should not be picked.
Which spots suit laser?
Sun spots, freckles and some brown spots may suit laser. A mark that is new, growing quickly, irregular in border or changing in colour needs dermatological assessment before any laser.
Not everything that looks like a spot is harmless. Some skin cancers and mole-like lesions can resemble a spot, and treating them with laser can delay diagnosis. In doubtful cases dermoscopy and, if needed, biopsy come first.
Laser can also be used for some birthmarks lying deeper in the dermis, but response and the number of sessions depend on the type of lesion. See the page on pigmentation and melasma for the distinctions.
Why can laser be risky in melasma?
Melasma is a pigmentation disorder sensitive to hormones, sun and heat. High-energy laser can worsen it or cause it to return.
The basis of melasma management is usually sun protection, topical lightening treatment and, where needed, medication or procedures. Laser is considered in a few selected cases, at low energy and under specialist supervision, and the outcome can be unpredictable.
Sun and heat trigger melasma, and it can recur even after treatment. The topic is covered in more detail on the pigmentation and melasma page.
How many sessions are needed and how is progress followed?
A clear, superficial sun spot may lighten in one or a few sessions; deeper or widespread spots need more. A few weeks are usually left between sessions.
Colour, depth, size and skin tone affect the number of sessions. Not every spot lightens to the same degree; some respond partly or may return.
Sun protection after each session is very important; unprotected exposure can undo results and produce new spots.
What are the risks and what should I do afterwards?
Redness, crusting and temporary darkening are common. Less often, lightening, lasting colour change, scarring and infection can occur. Sun protection is essential.
The risk of pigment change is higher in tanned skin, skin recently exposed to sun and darker skin tones, which is why timing and a test pulse matter.
Do not pick crusts, use a broad-spectrum sunscreen and follow the care the doctor advises. General principles are on the laser aftercare page.
Frequently asked questions
Is pigment laser suitable for everyone?
No. The type of spot, skin tone, hormonal status and sun exposure decide suitability. Melasma and doubtful lesions need extra care or a different assessment first.
Can the spot come back after laser?
If the skin is not protected from sun and the tendency continues, new spots can form or the old one can return. Regular sun protection is the most important precaution.
What is the difference between Q-switched and picosecond lasers?
Both break up pigment with short pulses; picosecond pulses are shorter. Which suits a given spot depends on the spot, the skin and the available device, and the doctor decides.
Can a mole be removed with laser?
Dermatological assessment is advised before treating a mole with laser. If a suspicious mole is removed this way, a diagnosis may be missed.
Can pigment laser be done during pregnancy?
Cosmetic laser is usually postponed. Spots that appear in pregnancy sometimes fade on their own after birth; follow-up and timing are decided with the doctor.
Sources (4)
- International Journal of Dermatology (Latin American consensus panel): Latin American consensus on the treatment of melasma (2024)
- Journal of Clinical Medicine: Management of Melasma: Laser and Other Therapies-Review Study (2024)
- Postępy Dermatologii i Alergologii: Lasers' Q-switched treatment in skin and subcutaneous lesions - review (2023)
- American Academy of Dermatology: Skin conditions that lasers can treat
This content is for general information and does not replace a personal medical assessment.