Hyperpigmentation is a category, not a competing diagnosis, even if 'vs' makes the terminology sound like a skincare tournament. Acne marks, freckles and sun spots also belong to that category. If you mean dark marks left after a breakout, the closer comparison is postinflammatory hyperpigmentation versus melasma.3
How do the dark patches differ?
| Feature | Postinflammatory hyperpigmentation | Melasma |
|---|---|---|
| Typical appearance | Irregular marks where skin was previously inflamed or injured. | Flat, blotchy patches, usually on both sides of the face. |
| Common locations | The sites of previous acne, eczema, burns or other injuries. | Cheeks, forehead, nose, chin and above the upper lip. |
| Colour | Light brown to black; deeper pigment can look grey or purple brown. | Tan, brown, greyish brown or bluish grey. |
| Triggers | Skin inflammation or injury. | Sunlight, hormonal changes and inherited susceptibility. |
| Course | Can persist for months or years. | Can last for years and return after treatment. |
A mark that follows the exact location of a healed spot or rash points toward postinflammatory pigmentation. Facial patches without a preceding injury can fit melasma, but appearance alone is not enough to confirm the diagnosis. Melasma itself is not cancer; other causes of dark spots can resemble it.45
Why does melasma happen?
The exact cause is not fully understood. Pigment producing cells become more active, with sunlight, pregnancy and some medications acting as possible triggers. Melasma is more common in women, particularly between ages 20 and 40, and family history increases the risk. You do not have to be pregnant to develop it.67
Does the difference change treatment?
Yes: treatment needs to address the cause, not just the colour. A product sold for 'dark spots' does not tell you which type of pigmentation you have, because the front of a bottle is not a dermatology appointment.3
- For marks after acne or eczema, treating the underlying inflammation helps recovery. Lightening treatments include azelaic acid, hydroquinone and retinoids.
- For melasma, treatment usually starts with daily sun protection and creams. A dermatologist can prescribe a combination of hydroquinone, tretinoin and a topical steroid when appropriate.
- For either condition, peels and lasers need careful selection. Injury from a procedure can cause more pigmentation; melasma also carries a risk of relapse.
Use broad spectrum SPF 50 or higher sunscreen daily on exposed areas with postinflammatory marks. For melasma, choose SPF 50 or higher sunscreen containing iron oxides, and add a wide brimmed hat and sun avoidance. Both ultraviolet and visible light can promote melasma pigmentation, so protection remains part of treatment after the patches fade.24
More treatment is not necessarily better. Excessive or improper use of hydroquinone, retinol or alpha hydroxy acids can worsen upper lip melasma. Irritating treatments can also darken melasma in darker skin tones. If treatment causes irritation or worsening pigmentation, have the routine reviewed rather than increasing use.56
How long does fading take?
Postinflammatory marks fade slowly, with weeks or months of treatment often needed. Melasma is also slow to respond, especially when longstanding. Pigment near the skin's surface generally responds better than deeper melasma pigment. Melasma treatments can fade patches but cannot prevent them from returning forever.235
When should you see a dermatologist?
Get an assessment if you are unsure what is causing the discolouration, or if a nonprescription melasma treatment has not helped within three to six months. Widespread darkening can have causes beyond melasma, including medications and internal disease. During pregnancy, wait until after birth to start melasma treatment; the patches sometimes improve after delivery.15
Where this answer comes from
- 1Hyperpigmentation - Skin Disordersmerckmanuals.com
- 2Melasma (facial pigmentation)dermnetnz.org
- 3Pigmentation Disorders: Diagnosis and Managementaafp.org
- 4Postinflammatory hyperpigmentationdermnetnz.org
- 5Melasma: Overviewaad.org
- 6Melasma Mustache: Causes and Treatmenthealth.clevelandclinic.org
- 7Melasma: Causesaad.org
