What Causes Hyperpigmentation? The Main Causes and What to Do About Each

What causes hyperpigmentation? In short: your pigment cells (melanocytes) are making more melanin in one area than the cells around them, and something is telling them to.

That "something" is the key to treating it. Here are the main triggers and what works for each.

How does skin make pigment in the first place?

Melanocytes sit in the lowest layer of the epidermis and produce melanin, which gives skin its color and absorbs UV. They pass melanin to neighboring skin cells. When signals such as UV light, inflammation or hormones ramp up the enzyme tyrosinase, more melanin is produced and passed on.

Everyone has melanocytes, regardless of skin tone. People with medium and deeper skin tones have more active ones, which is why hyperpigmentation is more common and lasts longer in those skin tones.

What are the main causes of hyperpigmentation?

How does the sun cause dark spots?

UV light is a direct signal to melanocytes to make more pigment as protection. Over years, some clusters of cells stay switched on, leaving sun spots. Visible light, including from indoor bulbs and screens, can also darken pigment in deeper skin tones, which is why iron oxide in tinted sunscreen matters.

See our step-by-step in how to get rid of sun spots.

How does inflammation cause hyperpigmentation?

Pimples, rashes, burns, cuts, bug bites and aggressive skin treatments release inflammatory molecules that boost melanin production. The result is post-inflammatory hyperpigmentation (PIH). It is the most common reason people search for help with dark marks. We cover it in post-inflammatory hyperpigmentation treatment.

Can hormones cause dark patches?

Yes. Estrogen and progesterone shifts, such as during pregnancy or when taking certain hormonal contraceptives, can trigger patchy darkening on the face. That pattern is typically melasma, which responds to a different treatment plan than ordinary dark spots, so a clinician should confirm the diagnosis.

Can medications or products cause pigmentation?

Some medications, including certain antibiotics, chemotherapy drugs, antimalarials and some others, can cause skin darkening in some people. Fragranced products, essential oils and certain perfumes can also trigger photo-sensitive pigment, especially with sun exposure. If you suspect a medication, do not stop it yourself. Ask the prescriber.

Can skin care products themselves cause dark spots?

Yes, indirectly. Harsh scrubs, strong acids used too often, over-exfoliation and products you are allergic to can inflame skin, and inflammation leaves marks. Fragrance and certain essential oils can cause a sun-triggered reaction called phytophotodermatitis, which looks like streaky dark patches after sun exposure. If new darkening followed a new product, stop it and see what happens.

What about genetics and skin type?

Skin tone affects how easily pigment reacts and how long it lingers, and family history plays a role in conditions like melasma and freckling. You cannot change genetics, but you can change triggers, which is the part that matters.

How can you tell which type you have?

Use clues. Where is it? Sun spots favor the face, hands and chest. Post-inflammatory marks sit exactly where you had a pimple, rash or injury. Melasma tends to be symmetrical across the cheeks, forehead and upper lip. When did it begin? After pregnancy or a new medication points toward hormones or drugs. How does it feel? Raised, rough or itchy patches are not simple pigment and deserve a medical look.

Photos help. A clinician can often identify the type from a few clear pictures, and a Wood's lamp or exam can show how deep the pigment sits.

Why does the cause change how long treatment takes?

Superficial pigment, the kind that sits in the top skin layer, often fades in a few months. Deeper pigment, found in the dermis, can take much longer and may only partly respond. Triggers that keep happening, such as daily sun or repeated pimples, reset the clock each time. So the quickest way to fade a mark is to remove the thing creating it.

How do you treat hyperpigmentation once you know the cause?

1. Remove or reduce the trigger. Sun, picking, shaving irritation or friction.
2. Wear SPF 30+ daily. This is the foundation for all treatments.
3. Use a pigment-targeting active. Niacinamide, azelaic acid, vitamin C, kojic acid or a retinoid for mild cases.
4. Step up if needed. A prescription cream such as the Vuret Hyperpigmentation Flare Control Cream (hydroquinone 6%, tretinoin 0.05%, kojic acid 4%, niacinamide 4%) for stubborn spots.
5. Consider procedures. Peels or lasers for what remains.

For the full menu, see best hyperpigmentation treatments.

What does not cause hyperpigmentation?

A few myths are worth clearing up. Dirty skin does not cause it, so scrubbing harder will not help. Eating or drinking certain foods does not directly cause dark spots, though a diet that fuels inflammation may worsen acne. Sweating does not cause pigment on its own, although friction and trapped moisture can. And mild, brief sun exposure is not the only culprit: it is the buildup over years that does the damage.

When is dark skin a sign to see a doctor?

Get checked in person if a spot is raised, changing, bleeding or has irregular borders, if dark patches are thick and velvety, or if darkening appeared suddenly across large areas. Those can reflect conditions that need medical attention.

Hydroquinone and tretinoin are not for pregnancy, and compounded medications are not FDA-approved. A physician decides if the cream is appropriate. Start your online visit to find out.