Why does my skin look darker sometimes?

What can make skin darker?

Sun exposure can cause pigment changes, including spots on areas regularly exposed to sunlight. With age, skin generally becomes thinner and paler, but pigmented spots can still appear on exposed areas. Sun related spots are often called age spots or liver spots, so even the names are not especially helpful. Comparing exposed areas with skin usually covered by clothing can help you notice the pattern of sun related changes.4

After acne, inflammation can leave extra pigment behind. This is called postinflammatory hyperpigmentation, and it is more common in darker skin tones. A color change is not necessarily a permanent acne scar: pigmentation and changes in skin texture are separate problems, although they can occur together. Acne related color changes often improve over months or longer.5

Hormone changes during pregnancy or puberty, melasma, and some medicines can also cause darkening. Medicines involved include birth control pills and drugs that increase sensitivity to light. A clinician will ask when the change began and what medicines you take; sometimes blood tests help check for vitamin deficiencies or hormone and thyroid problems.1

A previously pale patch can darken as its natural color returns after a rash, insect bite or wound. Improvement can begin within a few weeks if the original problem healed quickly. Longer lasting inflammation can mean slower or incomplete recovery. Sunlight can also push a recovering light patch into producing too much pigment, turning it into a dark spot. New or worsening light patches, or no change after a few weeks, need a dermatologist's assessment.6

What should you do first?

1. 1Identify the trigger. Notice whether darkening followed a breakout, injury or new skin or hair product. Treating ongoing acne, eczema or psoriasis helps stop new marks.
2. 2Stop using a cosmetic product that burns or stings. Choose gentle products labeled for sensitive skin or fragrance free.
3. 3Apply broad spectrum SPF 30 or higher sunscreen every day. For dark spots in darker skin tones, choose a water resistant tinted sunscreen with iron oxide to protect against visible light as well as ultraviolet rays.
4. 4Apply sunscreen to uncovered skin before going outside. Reapply every two hours outdoors and after swimming or sweating, and wear a wide brimmed hat.
5. 5Ask your prescriber about suspected medicine related darkening. Do not stop prescribed medicine yourself.

How long does darker pigmentation last?

After the trigger stops, a spot a few shades darker than your usual skin color generally fades within 6 to 12 months. Deeper pigment can take years. Treatments can help, but new spots can develop. Never apply liquid bleach to skin.2

A clinician can help select an appropriate cream or procedure based on the cause. Options include azelaic acid, vitamin C and prescription treatments; improvement can take months.1

When should you see a doctor?

Hyperpigmentation itself does not cause pain or itching. See a clinician if darkened skin is red, hot, itchy, painful or leaking blood or pus.1

Darkening alongside extreme tiredness, weight loss, loss of appetite or dizziness on standing also deserves a medical appointment. Addison's disease, a rare condition involving glands above the kidneys, can cause this combination. These symptoms overlap with other conditions, so skin color alone cannot identify the cause.7