Brown spots are incredibly common, particularly on areas of skin that have seen years of sun exposure. But although freckles, sunspots and other pigmented marks may look similar, they don't necessarily behave in the same way — and not every brown spot is appropriate for laser treatment.
Living in Australia means our skin is exposed to relatively high levels of ultraviolet (UV) radiation throughout our lives. Over time, this exposure can contribute to changes in pigmentation, particularly on the face, neck, décolletage, shoulders, forearms and hands. Some pigmentation has been present since childhood. Other spots gradually appear with age. Some become darker after summer and fade during winter, while others remain relatively persistent.
So why does this happen? The answer begins with a pigment called melanin.
What Gives Our Skin Its Colour?
Melanin is the natural pigment responsible for much of the colour in our skin, hair and eyes. It is produced by specialised cells called melanocytes, which are located primarily within the basal layer of the epidermis — the lower part of the outer layer of the skin.
Interestingly, people with different skin colours do not necessarily have dramatically different numbers of melanocytes. Much of the variation in skin colour relates instead to how much melanin is produced, the type of melanin produced and how pigment-containing structures called melanosomes are distributed and processed within the skin (Brenner & Hearing, 2008).
Melanin has an important protective function. When skin is exposed to ultraviolet radiation, melanocytes can increase pigment production. This helps absorb and disperse some UV radiation and provides a degree of protection to cellular DNA. This is why skin may tan after sun exposure.
However, repeated UV exposure can also disrupt the normal regulation of pigmentation. Over time, some areas may begin producing or retaining more pigment than the surrounding skin. The result can be the brown spots and uneven pigmentation we associate with cumulative sun exposure and ageing.
Why Does Sun Exposure Cause Brown Spots?
Ultraviolet radiation affects many structures within the skin. Repeated exposure can influence melanocyte activity, cellular signalling and the way pigment is distributed. Over many years, this can produce localised areas where melanin becomes more concentrated.
Importantly, sun damage is cumulative. The pigmentation appearing on your skin today may partly reflect UV exposure that occurred many years earlier. This is why brown spots often become more noticeable with age, particularly on chronically sun-exposed areas. The backs of the hands, face, forearms, shoulders and upper chest are common examples.
Genetics also matter. Two people with similar sun exposure may develop very different amounts and patterns of pigmentation because their skin responds differently to UV radiation.
(Brenner & Hearing, 2008; Cestari et al., 2022)
Freckles: Ephelides
What most people simply call freckles are medically known as ephelides. They are usually small, flat, light brown to darker brown, multiple rather than isolated and more noticeable after sun exposure.
Freckles commonly begin during childhood and are strongly influenced by genetics. They are particularly common in people with fair skin and certain variants of the MC1R gene, which influences pigmentation characteristics.
An important feature of freckles is that they often darken with UV exposure and become lighter when sun exposure decreases. The melanocytes are producing more pigment, but there is not necessarily a large increase in the number of melanocytes themselves. This helps explain why freckles may appear much more prominent during summer and fade during winter.
Sunspots: Solar Lentigines
Solar lentigines are often called sunspots, age spots or liver spots. Despite the traditional term liver spot, they have nothing to do with liver function. Solar lentigines are benign pigmented lesions associated predominantly with cumulative UV exposure. They commonly appear on the face, backs of the hands, forearms, shoulders and upper chest and décolletage.
Unlike freckles, solar lentigines usually develop later in life and tend to persist even when sun exposure decreases. They may range from light tan through to darker brown and can vary considerably in size. At a cellular level, solar lentigines involve more complex changes than ordinary freckles, including altered pigmentation and structural changes within the epidermis associated with chronic sun exposure.
(Cestari et al., 2022)
Freckles vs Sunspots: What's the Difference?
Both are generally benign. Although they can look similar, there are some useful differences. However, appearance alone should not be used by patients to diagnose a pigmented lesion.
Freckles typically begin earlier in life and have a strong genetic component. They are often numerous and relatively small. They Become darker with sun exposure and may fade significantly during periods of reduced UV exposure.
Solar Lentigines commonly occur on chronically sun-exposed areas and become more common with age. They are associated with cumulative sun exposure, tend to remain visible throughout the year and may become larger or more numerous over time.
What Does “Benign Pigmentation” Actually Mean?
Benign simply means non-cancerous. In a laser clinic, benign pigmentation may include appropriately assessed conditions such as freckles and solar lentigines. But there are many other reasons an area of skin may appear brown. These include:
Post-inflammatory hyperpigmentation
Melasma
Seborrhoeic keratoses
Melanocytic naevi (moles)
Pigmentation following injury or inflammation
Medication-related pigmentation
Other dermatological conditions
More importantly, some pre-cancerous or malignant skin lesions can also contain brown or black pigment. This is why the term brown spot is a description — not a diagnosis.
Why I Don't Simply Laser Every Brown Spot
Laser treatment works by delivering energy that is absorbed by particular targets within the skin. For many pigment-targeting lasers, that target is melanin. This can make laser treatment very effective for selected benign pigmented lesions.
But the ability to remove visible pigment also creates an important safety consideration. If the diagnosis of a pigmented lesion is uncertain, simply removing the pigment can alter its appearance without addressing the underlying pathology. It may also make subsequent clinical monitoring or diagnosis more difficult.
For that reason, my first question is not: "Can this pigment be removed?" It is: "Is this appropriate to treat?" which are very different questions.
Why Assessment Comes Before Laser Treatment
Before treating pigmentation, I assess factors including:
The type and appearance of the pigmentation
How long it has been present
Whether it has changed
The location and distribution
Skin type and skin tone
History of sun exposure
Previous treatments
History of post-inflammatory pigmentation
Relevant medical history and medications
In Western Australia, a skin check must be undertaken by a qualified medical practitioner prior to any laser treatment of pigmented lesions. If a lesion is uncertain, changing or has features that require further assessment, I do not treat it cosmetically. Laser treatment should never be used as a substitute for diagnosis. Any new, unusual or changing pigmented lesion during treatment requires additional medical assessment.
Why Australia Requires Particular Caution
Australia has one of the highest incidences of skin cancer in the world. Our high levels of UV exposure mean that sun-damaged skin commonly contains a mixture of pigmentation, vascular changes and other lesions. A face or décolletage with multiple sunspots may also contain lesions that should not simply be assumed to be cosmetic pigmentation. For this reason, careful assessment and appropriate medical referral are particularly important when treating sun-exposed Australian skin.
What About Melasma?
Melasma is also a form of hyperpigmentation, but it behaves very differently from a simple freckle or solar lentigo. It usually presents as symmetrical areas of brown or grey-brown pigmentation, commonly affecting the cheeks, forehead and upper lip.
Melasma is influenced by several interacting factors, including UV exposure, visible light, hormonal influences, genetics, melanocyte activity and inflammatory and vascular signalling. Because the pigment-producing system remains active, simply targeting visible pigment does not necessarily address the underlying condition. In some circumstances, aggressive laser treatment can stimulate inflammation and make pigmentation worse.
For this reason, melasma requires a much more cautious approach than treating an isolated benign solar lentigo.
What About Pigmentation After Acne or Inflammation?
Skin can also become darker after inflammation or injury. This is known as post-inflammatory hyperpigmentation, or PIH. It may occur following, acne, eczema or dermatitis, burns, skin trauma, picking or scratching, cosmetic procedures or laser treatments. Inflammation stimulates melanocytes to produce additional pigment.
PIH can occur in any skin type but may be more persistent and clinically significant in darker skin tones. Again, this is biologically different from a solar lentigo. Treating all brown pigmentation in exactly the same way therefore makes little sense.
How Does Laser Treatment Target Benign Pigment?
When an appropriate benign pigmented lesion has been identified, laser treatment may be considered. Pigment-targeting lasers deliver specific wavelengths of light that are absorbed by melanin. The absorbed energy affects the concentrated pigment while treatment parameters are selected to minimise unnecessary injury to surrounding tissue.
With very short-pulse laser systems, including picosecond and Q-switched technologies, rapid energy delivery can create photoacoustic and photomechanical effects that help disrupt pigment-containing structures into smaller fragments. The body then gradually processes and clears this disrupted pigment.
The appropriate wavelength and treatment parameters depend on factors such as the type of pigmentation, the colour and depth or pigmentation, skin tone, the treatment area, previous response and the risk of post-inflammatory pigmentation.
More energy is not automatically better. The aim is to achieve an appropriate biological effect while minimising unnecessary inflammation and injury.
Why Skin Tone Matters. Melanin isn't only present in the brown spot we want to treat. It is also present throughout normal skin. In darker skin tones, there is more competing epidermal melanin available to absorb laser energy. This can increase the risk of unwanted effects such as post-inflammatory hyperpigmentation, hypopigmentation, excessive inflammation and/or burns or blistering if inappropriate parameters are used.
This does not mean people with darker skin cannot have pigment treatment. It means wavelength selection, treatment parameters and clinical judgement become particularly important. A conservative approach is often appropriate.
Will a Sun Spot Come Back After Laser Treatment?
An individual benign pigmented lesion may respond very well to treatment. However, laser treatment does not remove the underlying tendency to develop pigmentation. If your skin has accumulated decades of UV exposure, additional pigmentation may become visible over time. Some treated areas may also develop recurrent pigmentation. This does not necessarily mean the laser treatment “failed”. It reflects the ongoing biology of the skin and the effects of cumulative UV exposure. For this reason, ongoing sun protection is an important part of maintaining results.
Prevention Still Matters: Laser treatment can address selected visible pigmentation, but it cannot undo every effect of cumulative UV exposure. Reducing further UV exposure remains one of the most important strategies for preventing additional pigmentation and protecting long-term skin health. This includes broad-spectrum sunscreen, protective clothing, hats, shade and avoiding unnecessary direct sun exposure. Sun protection is not simply part of laser aftercare. It is part of managing pigmentation itself.
The Takeaway: Brown Is a Colour, Not a Diagnosis
Freckles and sunspots are common, and many benign pigmented lesions can respond well to appropriately selected laser treatment. But pigmentation is biologically complex. Brown marks can represent different conditions arising from different processes within the skin. Some are suitable for cosmetic laser treatment. Some require a cautious approach. And some should not be treated with a laser at all.
At Piko Laser Clinic, I don't begin by asking how quickly a brown spot can be removed. I begin by determining whether it is appropriate to treat. The safest pigment treatment starts with understanding what the pigment actually is.
Scientific References
Brenner, M., & Hearing, V. J. (2008). The protective role of melanin against UV damage in human skin. Photochemistry and Photobiology, 84(3), 539–549.
https://doi.org/10.1111/j.1751-1097.2007.00226.x
Cestari, T. F., Dantas, L. P., & Boza, J. C. (2022). Acquired hyperpigmentations. Anais Brasileiros de Dermatologia, 97(6), 757–770.
Passeron, T., & Picardo, M. (2018). Melasma, a photoaging disorder. Pigment Cell & Melanoma Research, 31(4), 461–465.
https://doi.org/10.1111/pcmr.12684
Plensdorf, S., Livieratos, M., & Dada, N. (2017). Pigmentation disorders: Diagnosis and management. American Family Physician, 96(12), 797–804.
Taylor, S. C., Grimes, P. E., Lim, J., Im, S., & Lui, H. (2009). Postinflammatory hyperpigmentation. Journal of Cutaneous Medicine and Surgery, 13(4), 183–191.
https://doi.org/10.2310/7750.2009.08077
Medical information disclaimer: This article provides general educational information and does not replace medical diagnosis or individual assessment. New, changing, unusual or uncertain pigmented lesions should be appropriately medically assessed before cosmetic laser treatment.