Burns and Pigmentation Changes after Laser and IPL: Darkening, Lightening and Scarring — Prevention and What to Do

Which symptoms are normal after laser and IPL?

Laser and IPL devices work by converting light energy into heat in the skin. This is why redness, mild swelling, a feeling of warmth and, after laser hair removal, small bumps around the hair follicles are common immediately after the procedure. These symptoms usually decrease within a few hours to a few days.

With some light treatments used for dark spots, it can also be expected that the targeted spots darken for a few days and then flake off as a thin crust. Asking your physician before the procedure which changes are expected for your treatment makes it easier to tell what is normal afterwards.

Why do laser and IPL burns occur?

Light is absorbed in the skin by a pigment called melanin. Even if the target is the hair root or a dark spot, if there is a lot of melanin in the surrounding skin or the energy delivered is too high for that skin, heat can spread beyond the target and cause a burn. Unsuitable device choice, unsuitable settings, inadequate patient assessment and lack of experience are listed in scientific publications among the main causes of burns.

• Skin that is tanned, has recently been exposed to the sun or has been on a sunbed
• Darker skin (higher types in the Fitzpatrick classification): because there is more melanin in the skin, it absorbs more heat.
• A wavelength or energy setting unsuitable for the skin type, repeated pulses on the same area, inadequate cooling
• Some medicines and herbal products that cause light sensitivity (for example some antibiotics, some diuretics and herbal products such as St John’s wort; ask a physician or pharmacist for a full list)
• Tanning or self-tanning lotions, permanent make-up or a tattoo in the area
• An inexperienced operator and a lack of medical supervision

The Fitzpatrick classification divides skin into six groups according to how easily it burns in the sun and how much it tans. Having darker skin does not mean the procedure cannot be done; however, it requires more experience and care in choosing the wavelength and settings. For details, see our articles “Laser Hair Removal” and “Fractional Laser”.

How can a laser burn be recognised?

A burn is sometimes felt during the procedure as a sharp pain that is different from what was expected; sometimes it only becomes noticeable hours later. A grey-white colour of the skin, blisters, areas that look wet and, in the following days, crusting may appear. Regular lines or square shapes resembling the outline of the device tip are a typical sign suggesting that the light was delivered to the skin with too much energy.

A burn can sometimes look similar to an infection or a cold sore flare-up. So when you see a blister, a wound or a crust, do not try to diagnose it yourself; the area needs to be seen by a physician.

Why do dark spots (darkening of the skin) occur after laser, and how long do they last?

One of the most frequently reported and potentially long-lasting problems after light treatments is post-inflammatory hyperpigmentation, that is, darkening of the skin due to irritation or a burn. As the skin heals, it produces excess pigment and the area looks darker than its surroundings. It is more common in darker skin and in skin exposed to the sun after the procedure.

Such dark spots usually fade gradually within months; however, the time varies from person to person and can sometimes be longer than a year. Sunlight clearly prolongs the process. Pre-existing pigmentation such as melasma can also darken after light treatments; on this subject, our article “Dark Spots and Melasma” can be a useful guide.

Lightening of the skin (hypopigmentation) and scarring: can they be permanent?

Less commonly, the skin may remain lighter than its surroundings as a result of the pigment cells being affected. This is called hypopigmentation. Some of it improves over time; however, it tends to improve more slowly than darkening and can sometimes last a long time. Light-coloured areas in the shape of the device tip after laser hair removal are a typical example.

Scarring is seen most often after deep burns, infection, picking off crusts and with lasers that remove the surface of the skin (ablative lasers). Early assessment by a physician and appropriate wound care can help reduce the risk of scarring. If you tend to form raised scars (keloids), it is important to say so before the procedure.

What is increased hair growth after laser hair removal (paradoxical hypertrichosis)?

Paradoxical hypertrichosis is when hair in or near an area treated with laser or IPL for hair reduction increases or becomes thicker instead of decreasing. It is rare and has mostly been reported on the face and neck. Its exact cause is not known.

It is not a burn or a dark spot and is not an emergency; however, when you notice it, you should tell your physician. Your physician will decide how to change the treatment plan. Because most studies on this subject are observational, the evidence is limited.

Eye injury: why are protective glasses essential?

When laser light reaches the eye, it can damage the eyelid, the front surface of the eye and, most seriously, the retina (the light-sensitive layer at the back of the eye). Retinal damage can lead to permanent loss of vision. In a large proportion of published cases, eye protection was either not used at all or was removed during the procedure.

• Throughout the procedure, both you and the operator need to wear protective glasses suited to the wavelength of the device being used.
• Treatments around the eyes and near the brows may require extra protection; procedures in these areas require special experience.
• If the glasses slip, are uncomfortable or you notice light, tell the operator to stop the procedure.
• With home-use devices too, do not expose your eyes directly to the light; be careful with mirrors and shiny surfaces.

Are home-use laser and IPL devices safer?

Devices sold for home use usually work at lower energy; this can reduce the risk of serious burns but does not eliminate it. Not following the skin type and hair colour restrictions in the instructions, tanned skin and repeated use on the same area increase the risk of burns and dark spots. Although reports of eye injuries with home devices are few, it has been noted that this may be due to under-reporting.

If a burn or dark spot develops with a home device, stop using it and show the skin to a physician. For devices without documentation bought from unknown sources, our article “Counterfeit Products and Unlicensed Treatments” may give you some guidance.

What should you do at home if you get a burn after laser?

1. Cool the area with cool (not ice-cold) water or with a clean, cool, damp cloth. Do not put ice directly on the skin.
2. Keep the area gently clean; do not rub or scratch it.
3. Take a photo of the area and call the physician who performed the procedure the same day. Tell them the date of the procedure, the type of device (if you know it) and the medicines you take.
4. If you cannot reach your physician and the burn is large, deep or very painful, go to an emergency department and say that you have had a laser or IPL treatment.
5. Protect the area from the sun while it heals: use shade, clothing and a hat; once the skin has closed, regularly apply the sunscreen your physician recommends.

What should you not do?

• Do not pop blisters or pick off crusts; this increases the risk of infection, dark spots and scarring.
• Do not apply home remedies such as toothpaste, yoghurt, butter, cologne or plant oils.
• Do not use steroid, antibiotic or skin-lightening creams unless a physician recommends them; do not treat yourself with prescription medicines.
• Do not have a peel, use acid-containing products, scrub with an exfoliating mitt, wax or have a new laser session until the area has healed.
• Do not sunbathe or use a sunbed.
• Do not wait for days thinking it will go away on its own; early assessment can affect the outcome.

What are the treatment options? What can a physician do?

The physician first determines whether the problem is a burn, an infection, a cold sore flare-up or an allergic reaction. For a burn, wound care, suitable dressings and close follow-up until the skin heals are usually planned. If infection or a cold sore is suspected, appropriate medication can be started.

If a dark spot develops, the basic approach is strict sun protection; if necessary, the physician may recommend skin-lightening creams, and time may be allowed for the spot to fade on its own. If a scar or long-lasting colour change develops, a specialist physician can consider different treatment options. A new light treatment on the same area is usually postponed until the problem has resolved. For the general process, see our article “What Should You Do If a Complication Occurs after an Aesthetic Treatment”.

What can be done to reduce the risk?

• In the weeks before and after the procedure, do not sunbathe, use a sunbed or use tanning lotions.
• Before the procedure, mention all the medicines and herbal products you take, any history of cold sores and any tendency to scarring.
• Ask for your skin type to be assessed and, if necessary, for a test pulse on a small area.
• Ask who will perform the treatment, with which device and under which physician’s supervision.
• Do not remove the protective glasses during the procedure.
• If you feel a sharp pain that is different from what you expected during the procedure, say so immediately.
• When choosing a clinic, make use of our article “A 10-Point Safety Checklist for Choosing a Clinic and Physician for Medical Aesthetics”.

Limits of the evidence: how often burns, dark spots and paradoxical hypertrichosis occur varies greatly depending on the device, skin type, area and operator; many of the studies are retrospective and small. For this reason, you cannot be given a personal risk figure. This page is for general information and does not replace an examination.