Dark Spots, Melasma, or Post-Acne Marks? How to Tell Them Apart

Quick answer: Sunspots, melasma, and post-acne marks can all look like brown or dark patches, but they differ in shape, location, and cause. A dermatologist or skin specialist can confirm which type you're dealing with if you're not sure.

What's the difference between melasma and sunspots?

• Sunspots (solar lentigines) are typically small, well-defined, and roughly round or oval. They develop from cumulative sun exposure and tend to appear on the face, shoulders, backs of the hands, and chest as separate, distinct marks.
• Melasma usually presents as larger, less defined patches of brownish or greyish-brown pigmentation, often appearing symmetrically on both sides of the face — commonly across the cheeks, forehead, upper lip, or bridge of the nose.

According to the British Association of Dermatologists, melasma is strongly linked to a combination of sun exposure and hormonal factors, which is why it's more common during pregnancy, with hormonal contraception, or with certain hormone therapies, and why it can be more stubborn to treat than typical sunspots. Melasma also tends to be more reactive to heat and light in general, sometimes worsening with visible light exposure and not just UV. Because melasma can be more complex to manage and can sometimes worsen with certain treatments if approached incorrectly, it's generally advisable to seek a professional opinion rather than guessing. If your pigmentation is symmetrical, patchy, and concentrated around the cheeks or upper lip, melasma is a reasonable possibility worth having assessed by a dermatologist — you can find more background via the British Association of Dermatologists' patient information site. Our pigmentation collection can support general tone-evening, but a proper diagnosis should come first.

How do I know if it's PIH or melasma?

Post-inflammatory hyperpigmentation (PIH) is dark marking that appears specifically where the skin has recently been through some form of inflammation or injury, most commonly a healed spot, pimple, cut, or irritation. The key identifying features are location and history:

• PIH appears exactly where a blemish or injury was, and fades gradually over weeks to months, particularly with consistent SPF use to prevent the mark from being reinforced by UV exposure.
• Melasma is not linked to individual blemishes; it develops independently, often as broader, more symmetrical patches, driven mainly by hormonal factors combined with sun and light exposure.

One helpful way to think about it: if you can point to a specific spot and say that's where a pimple was, it's more likely PIH. If the pigmentation is spread more broadly across both cheeks or the forehead without a clear history of blemishes in that exact spot, melasma becomes more likely. Because the two can sometimes overlap, or be mistaken for one another, especially in acne-prone skin, the most reliable way to know for certain is a professional assessment. Brightening ingredients such as those in our vitamin C and niacinamide ranges are commonly used to help support an even tone for PIH, but if you're unsure which type of pigmentation you have, a consultation is the best starting point for tailored advice.

Not sure which type of pigmentation you're dealing with? Our team can help you understand what you're seeing and recommend a suitable next step. Book a consultation or browse our pigmentation and dark spot collection.

Educational content only — not medical advice. If pigmentation is spreading, unclear in origin, or not improving, a dermatologist can confirm the type and recommend the right approach.

Dr. Tanveer Ahmed
MBBS/FCPS · Founder & Clinical Director, Celsia Skin View profile