Principles of Treatment
- Mechanism: pigment laser works on the principle of selective photothermolysis: a wavelength is chosen to be preferentially absorbed by melanin. The energy of the beam fragments the pigment into smaller particles that are progressively eliminated by natural mechanisms (phagocytosis, epidermal renewal).
- Types of devices: commonly used technologies include Q-switched (nanosecond) and picosecond lasers. The choice of device depends on the type and depth of pigmentation, as well as skin phototype.
- Personalisation: the protocol is adapted based on the type of spot (solar lentigo, post-inflammatory hyperpigmentation, melasma), location, and skin colour. A prior assessment is necessary to reduce risks and optimise safety.
Session Process
- Prior consultation: during the initial consultation, the physician performs a detailed skin examination, clarifies the patient's history (phototypes, sun exposure, current treatments), identifies contraindications, and explains alternatives (peels, depigmenting creams, photoprotection). A personalised treatment plan is proposed.
- Before the session: avoiding sun exposure, tanning sessions, and certain treatments (retinoids, recent hair removal) for several weeks may be required. A test on a restricted area may be performed to assess the skin's reaction.
- Process: the session generally lasts between 10 and 30 minutes depending on the area treated. The skin is cleaned; cooling devices or anaesthetic creams may be used to improve comfort. The practitioner adjusts the energy and appropriate wavelength. Laser impacts are felt as tingling or mild electric sensations.
- Comfort and precautions during the session: protective glasses are worn. It is important to mention any intense pain, history of infection, or use of photosensitising medications.
Post-treatment Course and Results
- Immediate post-treatment effects: redness, slight swelling, possibly a "burnt" superficial effect, or a darkening of the spot before its elimination (darkening effect). Very superficial crusting may form for a few days.
- Onset of results: spot attenuation may appear within a few days to several weeks, depending on pigment depth. Some superficial spots respond in 1 to 2 sessions; others, notably melasma, require a progressive approach and several spaced treatments.
- Duration of results: duration is variable and depends on the cause of pigmentation, sun exposure, and post-treatment care (photoprotection). Sun-related spots may reappear without adequate sun protection.
- Individual variability: responses are individual; the physician specifies realistic expectations during the consultation.
Contraindications and Precautions
- Main contraindications: pregnancy and breastfeeding, active skin infection in the area, recently tanned skin, recent isotretinoin use (depending on protocol), history of keloid scarring or severe healing disorder without specialist evaluation.
- Darker phototypes: darker skin (phototypes IV–VI) carries a higher risk of post-treatment hypo- or hyperpigmentation; a prior test and increased caution are necessary.
- General precautions: discontinue irritating treatments (retinoids, exfoliants) before and after the session as recommended; avoid sun exposure and apply high SPF photoprotection (SPF 50+) after treatment; avoid tanning sessions or UV exposure.
Risks and Possible Side Effects
- Common and transient effects: redness, swelling, sensation of warmth, transient darkening of the spot, formation of small crusts.
- Less frequent risks: superficial burn, local infection, scar, depigmentation (lighter patch), or post-inflammatory hyperpigmentation. These effects may sometimes require additional treatment.
- Management of complications: risks and their prevention are explained during the consultation. In case of persistent adverse effects, medical follow-up is organised.


