- Postinflammatory hyperpigmentation can result from injuries such as cuts and scrapes or inflammatory skin conditions such as psoriasis and acne
- It is characterized by dark pigmented patches of skin that form as part of the healing process
- Melanin determines skin color and is produced by cells called melanocytes
- Skin of color contains greater amounts of melanin and is therefore at higher risk
- There are many effective treatments available including over-the-counter and prescription topicals as well as professional treatments
Postinflammatory hyperpigmentation (PIH) is a very common acquired skin disorder that develops due to injury or inflammation. It affects men and women equally, but is most predominant in skin of color.
Once an injury or inflammation heals, long-lasting dark spots or marks can take their place and be gray, brown, purple or black in color depending on skin tone and the depth of the injury.
What Is Postinflammatory Hyperpigmentation?
Hyperpigmentation refers to dark spots or patches of skin that are darker than the surrounding area. This discoloration occurs when melanocytes, which are responsible for melanin’s production and distribution, overproduce melanin in response to inflammation.
PIH refers to hyperpigmentation that is specifically triggered by injury and inflammation. Anyone is susceptible, but it impacts darker skin tones with greater frequency and severity, and can have long-term psychological and social effects.
Causes and Diagnosis
PIH can be caused by a skin injury such as cuts and scrapes and burns; or skin conditions, infections and allergic reactions. In skin of color, the main instigators are acne, atopic dermatitis and impetigo.
The skin produces melanin as part of the healing process and is a normal response to inflammation; the greater the severity of the injury the more prominent the hyperpigmented area will be in terms of size and color.
While these hyperpigmented areas do fade with time, one study examining PIH among acne patients found it was nevertheless long lasting: at least 1 year for more than 50% of patients and 5 years or longer in 22%.
These discolored areas of skin can be exacerbated due to exposure to damaging UV rays.
In an effort to protect itself from the sun, skin activates melanogenesis, the production of melanin pigments. These pigments also have antioxidant and scavenging properties to both protect and repair the skin.
To diagnose PIH, your care provider will use a Wood’s light to examine the skin, note the color of the hyperpigmented areas and take a complete history. If necessary, a biopsy will be made.
As an immediate first step, the inflammatory condition will be treated to reduce or prevent the progression, and a specific treatment or set of treatments will be chosen.
Is Postinflammatory Hyperpigmentation Permanent?
PIH typically fades with time and eventually resolves altogether. This is due to the skin naturally regenerating about every 30 days; pigmented skin cells naturally shed and are replaced by fresh cells which evens out tone.
Postinflammatory Hyperpigmentation Treatments
There are a number of solutions available to lighten hyperpigmented skin. Topical depigmenting creams can be used alone or in conjunction with other agents; procedures such as chemical peels or laser treatments and also be incorporated.
Topical agents are typically used to treat mild cases of PIH as they aren’t as effective for deeper pigmentation.
Along with UV protection, hydroquinone is first-line therapy for hyperpigmentation. It can effectively lighten skin by inhibiting tyrosinase activity which interferes with melanin production.
They can also be safely combined with retinoids and steroids as triple therapy for severe or widespread pigmentation.
Retinoids such as tretinoin are derivatives of vitamin A, and can lighten skin through several modes of action. It too inhibits tyrosinase activity, and both removes and disperses remaining melanin. It speeds up skin cell turnover to allow damaged cells to shed more quickly; it prevents dark spots from forming due to its anti-inflammatory properties.
Retinoids also help boost the efficacy of hydroquinone by enabling better penetration.
Chemical peels are considered second-line treatment, and are used to remove the outermost layer of the epidermis, the stratum corneum. This lifts away darkened skin cells, stimulates new growth and allows for evenly distributed melanin.
Chemical peels also stimulate collagen production which promotes healthy tissue formation and repairs skin. It also has amino acids which can reduce the appearance of dark spots.
When used in combination with topical solutions, a chemical peel can increase their effects.
There are a range of alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs) peels on the market, and they are classified as light, medium and deep peels depending on the concentration used to penetrate the skin. AHAs have a low risk of complications, even for darker skin tones.
In the case of PIH, glycolic acid is one of the most common AHAs due to its efficacy. It has also proven to be safe for skin of color: In one study comparing a topical regimen of hydroquinone and tretinoin with a glycolic acid peel, researchers concluded that the peel demonstrated greater and faster improvement, and superior skin lightening.
That being said, there is still a risk for increased hyperpigmentation in some cases. Proper skin preparation and peeling technique can mitigate this risk; this underscores the importance of choosing a professional with specific skill and knowledge of these peeling procedures.
Light- and low-level laser-based therapies are also established second-line treatments and offer a gentler approach than other types of lasers. This therapy works by targeting the middle layers of the skin to stimulate collagen which repairs damaged, hyperpigmented skin and improves texture.
In one study examining a low energy laser and skin of color, researchers found the treatments were safe, effective and had no side effects.
Lasers using Q-switched technology are also safe and effective; in one study, 84% of participants reported being satisfied to completely satisfied. As well, all side effects were temporary and resolved within 1 month.
- Azelaic acid has anti-inflammatory, antimicrobial and antikeratinizing properties
- Kojic acid is an antimicrobial and a potent antioxidant
- Licorice extract is an antimicrobial and anti-inflammatory, and can scavenge free radicals
- Vitamin C is an antioxidant and protects skin from UV damage
Are treatments covered by insurance?
While hyperpigmentation treatments aren’t covered by insurance, in some cases PIH is. There is an insurance code, ICD-10-CM Diagnosis Code L81.0 that can be used to indicate a PIH diagnosis for reimbursement purposes.
To find out if you qualify, speak to your dermatologist.
Before and Afters
Preventing Postinflammatory Hyperpigmentation
Preventative measures, such as promptly addressing skin injury and inflammation can reduce the risk of discolored skin.
One of the most important steps you can take is to protect your sun from damaging UV rays. This will act as a preventative to hyperpigmentation formation and eliminate any risk of worsening it.
- Wear a broad spectrum SPF 30 sunscreen every time you are outdoors; zinc formulas are nonirritating and provide superior protection
- Reapply sunscreen every 2 hours or more if you are perspiring
- Avoid being in direct sunlight during the peak hours of 10 am – 3 pm
- Wear a broad-brimmed hat
Treat your skin with care to avoid damaging the skin barrier and prompting inflammation:
- Opt for gentle skin care products that are formulated for your skin type
- Choose products that have active agents such as hyaluronic acid to deeply moisturize; niacinamide to boost ceramide production
- Follow your skin care regimen daily to ensure your skin is protected and healthy
- Avoid fragrances and comedogenic products to reduce the risk of inflammation
- Avoid toners, astringents and abrasive exfoliants that can overdry skin
Treat injuries and inflammation
- For any injury, clean the area immediately with mild soap and warm water
- If necessary, apply an antibiotic cream or ointment
- Wash your hands before and after to prevent any transfer of bacteria
- For small wounds, leave uncovered; otherwise place a bandage and change daily
- Do not pick at your skin; you can worsen inflammation
Postinflammatory hyperpigmentation is a very common skin condition, especially in skin of color; for this skin tone acne, atopic dermatitis and impetigo pose the greatest risk.
With time, pigmentation can fade on its own, but sometimes it is permanent. As well, it can be moderate to severe, and impact quality of life.
There are several treatment options available that work by suppressing tyrosinase activity and stimulating collagen production. These include topical agents as well as laser therapy and chemical peels. With melanin production under control, skin can shed damaged skin cells and collagen can repair, lighten and strengthen skin.
To reduce your risk of PIH, protect your skin from the sun, treat injuries promptly and follow an established skin care regimen.
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