What Causes Post-inflammatory Hyperpigmentation on Dark skin

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In post-inflammatory hyperpigmentation, the skin becomes darker in areas of previous injury or skin condition due to an increase in the pigment (melanin) that remains during the healing process. Sometimes darkening can also be due to the iron pigment that remains when old red blood cells die. Acne is not only a common cause of all kinds of skin injuries (scratches, cuts, burns, insect bites, chronic rubbing) but also many other skin conditions such as eczema (atopic dermatitis). 

Types of Post-inflammatory Hyperpigmentation

In addition to chloasma, sunspots, and post-inflammatory hyperpigmentation are other types of hyperpigmentation.

  1. Chloasma. Chloasma is caused by hormonal changes and is thought to occur during pregnancy. Areas of hyperpigmentation can appear anywhere on the body but are most common on the stomach and face.
  2. Black spots. Black spots, also called chloasma or sunspots, are common. It is associated with excessive exposure to sunlight over time. They usually appear as spots in areas exposed to sunlight, such as the hands and face.
  3. Hyperpigmentation after inflammation. This is the result of skin injuries and inflammation. A common cause of this type is acne.

Post-Inflammatory Hyperpigmentation Symptoms

Post-inflammation hyperpigmentation often looks like a flat discolored area of the skin. It ranges from white, pink, red, purple, brown, or black, depending on the color of the skin and the depth of extra shades.

PIH can occur on all skin types but tends to be more severe and long-lasting for people with moderate to dark skin. PIH affects both men and women equally.

Who causes post-inflammatory pigmentation?

The rich complexion makes post-inflammatory hyperpigmentation more likely. In these people, the color is darker than the fair skin color and tends to last longer. Pigmentation tends to be more pronounced in conditions caused by the sun, such as plant photodermatitis and lichen planus (inflammatory skin diseases such as erythema dysplasia).

Some drugs can also darken post-inflammatory pigmentation. These include antimalarials, clofazimine, tetracycline, bleomycin (erythema whip), doxorubicin, 5-fluorouracil, busulfan, etc. anticancer drugs.

Acne Scars vs. Post-Inflammatory Hyperpigmentation

If you find that PIH is not an actual wound, you can relax. It leaves scars on the skin for some time but is often referred to as “fake scars” because it does not damage hair follicles.

True acne scars occur when tissue is lost, resulting in depressions or collapsed areas, or when overgrowth leaves a raised spot on the tissue.

PIH, on the other hand, is straight. It does not puncture or bulge, but it is darker than the extra shades of skin.

Disappears over time

Fortunately, PIH can disappear over time without treatment. But the word that applies here is time. It can take 3 to 24 months for the PIH to fade completely, but it can also take longer.

PIH does not always disappear naturally. In some cases, it is more or less permanent.

There are treatments to help. It may not be possible to eliminate the extra shades, but it will be significantly brighter. Therapy can also reduce fading time if you do not want to wait for the wound to lighten naturally.

Alpha Hydroxy Acids (AHAs)

Alpha hydroxy acids, especially glycolic acids, are a good starting point for treatment. Alpha hydroxy acids (AHA) help speed up the skin’s natural exfoliating process and help improve the appearance of PIH.

There are many over-the-counter “brightening” treatments. Soaking applications such as lotions, creams, and gels give better results than washdown products such as cleansers.

More powerful AHA treatments are available by prescription. AHA is also often used as an anti-aging treatment to soften and smooth the skin.


The treatment for PIH is hydroquinone and is commercially available in prescription creams with 1% to 2% strengths and 3% to 4%. Hydroquinone works by brightening the skin by blocking the enzymes that cause melanin production.

In addition to hydroquinone, some lightening creams contain kojic acid, glycolic acid, tretinoin, and vitamin C-containing retinoids. These combination creams may give better results than hydroquinone alone.

Hydroquinone cream should only be applied carefully to dark areas to prevent unnecessarily lightening the natural skin tone. Hydroquinone can cause skin irritation in some people, so it is worth consulting with your doctor before starting hydroquinone therapy.

Topical Retinoids for rich complexion

Retinoids are often prescribed to treat acne on the skin. Acne is treated by regenerating the skin cells faster with retinoids. This rapid exfoliation also helps with the decline of PIH.

Retinoid cream contains retin-A (tretinoin) and retin-A micro, tazarotene (tazarotene) and diferin (adapalene). An additional benefit is the reduction of post-inflammatory pigmentation when treating acne formation.

Except for Differin, these drugs are only available by prescription. You may not see noticeable results for weeks or months after the start of treatment.

Beware of excessive dryness, redness, and irritation. This can trigger PIH automatically.

Azelaic acid

Azelaic acid is another drug used to treat PIH besides acne. It works by reducing inflammation and accelerating the turnover rate of cells. Azelaic acid may be used in combination with glycolic acid or tretinoin.

Several studies have shown that azelaic acid is as effective as hydroquinone in the treatment of hyperpigmentation. Hydroquinone is a good alternative for those who cannot use it.

Azelaic acid is only available by prescription. As always, monitor skin redness and inflammation and consult your doctor immediately if you experience any of these side effects.

Treatment in the office for rich complexions

PIH can be treated professionally by a dermatologist in a clinic. Treatments include a variety of chemical peels, laser, microneedles, and microdermabrasion.

However, a single treatment is not enough to eliminate hyperpigmentation. A series of treatments may be required at intervals of 2-4 weeks (depending on the procedure being performed). The treatment that’s right for you can be determined by your doctor.

How does hyperpigmentation affect extra shades?

Hyperpigmentation is severe and requires serious care, but there are some essential points to understand first:

People with rich complexions are naturally more susceptible to darkening. Because the shades of skin are already producing melanin, it becomes darker and more prone to hyperpigmentation when hormones and trauma cause increased melanin production.

The treatment of dark spots in people with extra shades is more challenging. It should be gentle enough not to irritate or worsen the skin sufficient to cause post-inflammatory hyperpigmentation.

People with extra shades have a significantly lower risk of overproducing melanin and have fewer restrictions on hyperpigmentation treatment. However, the more golden the skin color, the more likely it is that dark spots will occur due to sunburn damage.

Causes of Post-inflammatory hyperpigmentation

Post-inflammatory hyperpigmentation (PIH) refers to the skin’s darkening after an inflammatory rash or skin damage.

 Hyperpigmentation is caused by the reaction of melanocytes to skin damage, resulting in increased melanin production and redistribution. This pigmentation change is more likely to affect patients who have dark skin.

Post-inflammatory changes can occur in both the epidermis and dermis. Over-pigmented epidermal morphology increases melanin production and transfers to keratinocytes.

 In dermal PIH, the damaged basement membrane invades the dermis and is phagocytosed by dermal macrophages called melanophages. Macrophages can also migrate to the epidermis, phagocytic melanosomes, and then back to the dermis 17,18. Melanin in dermal melanophages can last for years.

In rich complexions, the skin can become hyperpigmented (PIH) or depigmented (known as post-inflammatory depigmentation) as it recovers from an acute inflammatory disease. There are a number of extra shades that are characterized by skin lightening or darkening, including but not limited to discoid lupus erythematosus, seborrheic dermatitis, tinea versicolor, atopic dermatitis, and sarcoidosis.

The medical history may include any previous type of inflammation or injury—acne, arthropod rash, viral rash, eczema, psoriasis, trauma. Physical examination findings include small to large hyperpigmented spots and patches of various sizes of any distribution. Although usually a clinical diagnosis, a biopsy for histopathological evaluation can help complex cases. 

Disorders such as chloasma, morphological abnormalities, atrofoderma, and other rarer etiologies should be considered in patients with no prior evidence of inflammation by history or laboratory examination.

 The time it takes for hyperpigmentation abnormalities to normalize is highly variable and is associated with many factors, including the patient’s fundamental skin tone, the type and intensity of injury and inflammation, and the patient’s sun exposure habits. 

It takes years and can be psychologically disturbing. You can try whitening agents, chemical peels, and laser treatments. However, it should always be used with caution as it can cause worsening of the original pigmentation.

Mature Dyschromia fo Extra shades skin

Darkening of facial skin tones can be seen on mature dark skin, even when not exposed to excessive sunlight. Maturity dyschromia or familiar heterogeneous tones can usually be defined as diffuse hyperpigmentation on the outside of the forehead and cheekbones. One study found that uneven skin tone was the main complaint of more than one-third of black women.

These changes in skin tone can be the result of years of chronic sun exposure. It can be misdiagnosed as mature dyschromia, chloasma, acanthosis nigricans, or PIH. This is an exclusion diagnosis, and allergic contact dermatitis or photoallergic dermatitis should be excluded. Treatment options include sunscreens, whitening agents, antioxidants, dermabrasion, and chemical peels.

Can post-inflammatory hyperpigmentation be reduced or removed?

In chemotherapy and laser therapy, skin symptoms can be relieved and recovery time sped up:

  • Chemical peeling involves applying a chemical solution (such as AHA) to exfoliate the skin (remove dead skin cells), promote new skin cell growth, and reveal a new skin surface. 
  • Laser treatment has a similar effect but tends to be more accurate because a dermatologist has more control over its intensity. Laser treatment “zapping” the affected area with high-energy light. The mildest treatments work on the epidermis (superficial layer) of the skin, whereas more intensive treatments are able to penetrate deeper layers.

Dermatologists may also prescribe and use hydroquinone, which is considered the most effective topical drug to reduce hyperpigmentation. However, like other types of chemical peels and laser treatments, it can only be used for a limited period, especially in people with phototypes 3-6. It can irritate the skin and cause post-inflammatory pigmentation.

Self-Care Guidelines for Rich Complexions

Most post-inflammatory pigments fade over time, but it takes months, and some areas (especially the legs) do not fade.

  1. Sunlight can be even darker, so wear clothing, a hat, and sunscreen (SPF 15 and above) to keep out of the sun.
  2. Makeup can be applied to cover the affected area. Waterproof makeup can be used on the arms and legs.
  3. If you suffer from an underlying skin extra shades such as acne, you should seek medical attention.
  4. Whitening creams are sold over-the-counter (0.5-2% hydroquinone in the US, more powerful overseas but can be dangerous concentrations), but the effectiveness of weaker foams is limited. There are safety concerns. They are being considered for removal from the market by the Food and Drug Administration (FDA). If you try it and it doesn’t improve after 4 to 6 months of use, discontinue use. Do not use more robust foreign products as they can exacerbate pigmentation and cause permanent pigmentation if overused.

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