Laser and Skin

Pigment spots: the cause decides

Pigment spots respond to laser, chemical peels or lightening creams, but the right choice depends on why they formed. Sun-related spots often fade within 1 to 3 laser sessions, hormonal melasma relapses without daily sun protection in up to 50% of cases tied to pregnancy, and spots left after acne or injury frequently clear on their own within 6 to 12 months. A doctor should confirm the diagnosis first, because a flat brown mark can occasionally hide something more serious.

Three causes, three timelines

Pigment spots form when melanocytes, the skin cells that make its colour, produce too much pigment in one place. Three triggers explain almost every case a dermatologist sees. Years of unprotected sun exposure produce flat, sharply bordered marks on the backs of the hands, the chest and the temples, the pattern generally called age spots. Hormonal shifts, chiefly pregnancy and hormonal contraceptives, drive melasma, a patchier and more symmetrical discolouration on the cheeks, forehead and upper lip. Inflammation, from acne, burns or an overly aggressive treatment, leaves a mark exactly where the skin was injured.

Family history plays a part too: about 60% of people with melasma report a relative with the same pattern, and hormonal contraceptives or pregnancy sit behind about 25% of cases in affected women. Up to 50% of pregnant women develop some degree of melasma, and much of it fades after birth once the sun stays covered. Marks left after inflammation are more common and more stubborn in darker skin tones, where they persist noticeably longer than in lighter skin.

How to tell the three types apart

Sun-related spots are sharply bordered, an even light to mid brown, and sit on skin that gets the most daylight: the backs of the hands, the chest and the temples. They barely change from one year to the next. Hormonal melasma looks different: soft-edged, often symmetrical, and typically spread across the cheeks, forehead and upper lip rather than confined to a single patch.

Marks left by inflammation appear exactly where the skin was previously injured, whether that is a healed spot, a graze or an area treated too aggressively. They usually carry a reddish-brown tint and fade over 6 to 12 months in most people, though the timeline stretches further in darker skin tones. Treating all three the same way tends to make at least one of them worse, which is why the cause has to be identified before the method is chosen.

What the treatments actually do

Q-switched and picosecond lasers deliver their energy in pulses lasting billionths of a second, long enough to shatter melanin into fragments the body can clear but too short to heat the surrounding skin. Chemical peels using alpha hydroxy or salicylic acid lift the outer skin layers and take the stored pigment with them. Topical actives work more slowly: azelaic acid, vitamin C and niacinamide blunt new melanin production and show a visible result after 8 to 12 weeks, while a prescription cream combining hydroquinone, tretinoin and a mild steroid clears or improves melasma in 60 to 80% of people who use it correctly. Hydroquinone and tretinoin are avoided during pregnancy and breastfeeding, which matters because pregnancy is one of the main triggers of melasma in the first place. Non-prescription lightening creams are usually limited to 3 to 6 months of use before a dermatologist should take over.

Each method has a limit that matters more than the technology behind it. Without daily sunscreen, both sun-related spots and melasma tend to return, sometimes within a single summer. Melasma treated with laser carries a well documented risk of relapse and can become harder to treat afterwards, which is why lasers are generally reserved for age spots rather than hormonal marks. In darker skin tones, any physical treatment, including peels and lasers, can shift pigment the wrong way and needs a lower energy setting and a slower pace.

Diagnosis and timing come first

Before any lightening treatment starts, the mark itself needs to be identified correctly. Flat brown spots are usually harmless, but age spots are recognised as an independent risk factor for melanoma, and a biopsy is recommended whenever the diagnosis is uncertain or a mole looks unusual. Anyone with a mark that is changing shape, colour or size should read our guide on mole removal before booking a lightening session, because treating a mark first removes the option of examining the tissue afterwards.

Timing affects the result almost as much as diagnosis does. Clinics generally schedule pigment treatments for autumn and winter, because skin stays sensitive to UV light for 4 to 6 weeks after a laser session or a strong peel, and any sun exposure during that window can leave the mark darker than before. A broad-spectrum sunscreen of SPF 30 or higher, applied 15 to 30 minutes before going outside and reapplied roughly every 2 hours, is the baseline for that period and for melasma maintenance afterwards; guidance for marks left by acne generally calls for SPF 50 or higher.

What to expect from a laser session

After the mark is checked, the skin is cleaned and numbed if needed. The pulse feels like a quick pinprick or the snap of a thin elastic band against the skin. A single spot is treated in seconds, while a hand with several marks needs about 10 to 20 minutes under the laser. Most people need 1 to 3 sessions spaced 4 to 6 weeks apart, with the final colour only settling some weeks after the last one.

The treated spot typically darkens further over the first few days as the broken-down pigment rises to the surface, then forms a fine crust that sheds within 7 to 14 days. Sun, sunbeds and self-tanning products are avoided on the area for that period, alongside the daily sunscreen already mentioned. The Sun Exposure Timer can help plan safe outdoor time while the skin recovers.

Questions to ask before you book

Frequently asked

Do pigment spots come back after treatment?

Often yes without daily sun protection. Sun-related spots and melasma can darken again within a single season, while marks left by inflammation are less likely to return once the original irritation has healed.

Who should treat pigment spots?

A dermatologist should examine any flat brown mark first, since age spots are recognised as an independent risk factor for melanoma. Only a suitably trained practitioner should use a medical laser on the skin.

What season suits laser treatment best?

Autumn and winter suit it best. Skin stays sensitive to UV light for 4 to 6 weeks after each session, and summer sun can darken the treated area again before it has settled.

Do over-the-counter lightening creams work?

Ingredients such as azelaic acid, vitamin C and niacinamide slow new melanin production and show a visible result after 8 to 12 weeks. They work more slowly than laser and only with consistent daily use.

Can a pigment spot be dangerous?

Occasionally. A flat brown mark can rarely be an early form of skin cancer, which is why an examination should happen before any lightening treatment removes the tissue that would need checking.

What does laser treatment of a pigment spot feel like?

Most people describe a quick pinprick or the snap of a thin elastic band. A single spot is treated in seconds, while a hand with several marks needs about 10 to 20 minutes.

Sources

• DermNet NZ: Solar lentigines · cause, appearance, melanoma risk factor, biopsy guidance
• DermNet NZ: Melasma · hormonal causes, treatment options, laser relapse risk
• DermNet NZ: Postinflammatory hyperpigmentation · causes, duration by skin tone, treatment cautions
• British Association of Dermatologists: Melasma patient information leaflet · sun protection routine, laser warnings, pregnancy prevalence

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This guide is for general information. It does not replace medical or professional cosmetic advice or an examination.