In short. Epidermal and dermal pigment, why melasma behaves differently from freckles, and how a realistic pigment plan is built around sun protection and intervals.
Key points
- Ultraviolet and visible light both drive pigment production.
- Broad-spectrum sunscreen reapplied through the day, a hat, and shade protect the result of every session and reduce recurrence.
- A pigment plan without photoprotection is a plan that will fail, whatever device is used.
Pigmentation is the most requested laser treatment and the one most often oversold. Results depend far less on the device than on which pigment is being treated, at what depth it sits, and whether the underlying trigger can be controlled afterwards.
First, identify the pigment
Pigment that sits in the epidermis — freckles, sun-induced lentigines, and the flat brown patches of long-term sun damage — generally responds well and can clear substantially in a small number of sessions. Pigment in the dermis, such as the blue-grey patches of a nevus of Ota or the grey-brown of Hori nevus, lies deeper, needs longer wavelengths and more sessions, and clears more gradually. Melasma, a patterned brown discolouration on the cheeks, forehead, and upper lip, is a different problem entirely: it is not simply pigment to be removed but a reactive condition that light, heat, hormones, and inflammation can all worsen.
How pigment lasers work
Short, intense pulses in the nanosecond and picosecond range are absorbed by melanin and break pigment particles into fragments small enough to be cleared by the body’s own scavenging cells over subsequent weeks. This is why results appear gradually rather than immediately, and why the interval between sessions — typically several weeks — exists: the skin needs time to finish the job before being asked to do it again.
Why melasma requires restraint
Melasma is managed rather than cured. Aggressive laser treatment in melasma frequently makes it darker, because heat and inflammation stimulate further pigment production. Where laser is used at all, it is used gently, at low energy, often as one component of a plan that includes photoprotection, topical agents, and treatment of any contributing factors. Anyone offering guaranteed clearance of melasma is describing something that does not exist.
Sunscreen is part of the treatment
Ultraviolet and visible light both drive pigment production. Broad-spectrum sunscreen reapplied through the day, a hat, and shade protect the result of every session and reduce recurrence. A pigment plan without photoprotection is a plan that will fail, whatever device is used.
Sessions, maintenance, and recurrence
Most epidermal pigment clears in two to four sessions; deeper pigment may need more, with partial rather than complete clearance as the realistic aim. Recurrence is common, because sun exposure continues and melasma remains responsive to its triggers. Many patients settle into a pattern of an initial course followed by occasional maintenance, and that is an honest outcome rather than a failure.
When pigmentation needs medical review first
- A pigmented spot is new, changing in size, shape, or colour, or has an irregular edge or multiple colours, and must be assessed rather than lasered.
- You have melasma and are offered an aggressive, high-energy course promising complete and permanent clearance.
- A mole, a birthmark, or a lesion that bleeds, itches, or crusts is included in a cosmetic pigment plan without any diagnostic assessment.
Frequently asked questions
Why does melasma behave differently from freckles?
Because melasma is not simply pigment to be removed but a reactive condition that light, heat, hormones, and inflammation can all worsen. Aggressive laser treatment frequently makes it darker, so it is managed rather than cured, with gentle settings and photoprotection as part of the plan.
Why are sessions spaced several weeks apart?
Because the laser breaks pigment particles into fragments that the body then clears over subsequent weeks. Results appear gradually rather than immediately, and the interval exists so the skin can finish the job before being asked to do it again.
Why is sunscreen considered part of pigment treatment?
Because ultraviolet and visible light both drive pigment production. Broad-spectrum sunscreen reapplied through the day, a hat, and shade protect the result of every session and reduce recurrence. A pigment plan without photoprotection is a plan that will fail.
Risks & Limitations
- Burns and blistering if settings do not match the skin.
- Post-inflammatory hyperpigmentation, particularly in darker skin types, which may take months to settle.
- Hypopigmentation (lightening) of treated skin, which can be permanent.
- Scarring, including hypertrophic scarring, which is uncommon but real.
- Infection, including reactivation of herpes simplex after resurfacing.
- Acne or milia flare during recovery.
- Results are incremental and most concerns need several sessions. Melasma may rebound or worsen with aggressive treatment.
When to Seek Care
- Blistering, weeping or broken skin beyond the expected reaction.
- Severe pain that is worsening rather than settling.
- Spreading redness, warmth, pus or fever.
- New darkening or firmness that looks like scarring at the treated area.
- Any change in a treated pigmented lesion — it should be reviewed, not retreated.
References & Further Reading
- American Academy of Dermatology (AAD) — laser and energy device information
- American Society for Laser Medicine & Surgery (ASLMS)
- National Medical Products Administration (NMPA, China) — device registration status
- Cochrane Library — systematic reviews in laser dermatology
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.