Tuesday, May 17, 2022

How Acne Causes Hyperpigmentation: Prevention, Treatments, Remedies

  • Hyperpigmentation refers to spots and patches of skin that are darker than the surrounding area
  • It is caused by several factors including overexposure to the sun, skin injury and inflammation, as well as systemic disorders and skin reactions 
  • Anyone can be affected, but skin of color is most at risk 
  • Effective treatments include over the counter and prescription topicals, professional procedures and to a lesser extent, at-home treatments

Hyperpigmentation describes patches of skin that are darker than the surrounding area. Injury, sun exposure and skin conditions such as melasma and atopic dermatitis have all been identified as causing hyperpigmentation. Acne is another skin condition that falls within this category, and in this case, the discolored skin is referred to as postinflammatory hyperpigmentation.     

Can Hyperpigmentation Be Caused by Acne?

Yes, hyperpigmentation is a very common cause of acne and develops in both noninflammatory and inflammatory acne even if acne symptoms are mild. It develops due to a response to skin inflammation and injury but is also influenced by the intensity and duration.

Once acne lesions heal, they can leave behind dark spots in their place, called postinflammatory hyperpigmentation (PIH) This occurs when the body responds to inflammation and triggers an overproduction of melanin as part of the healing process. 

Melanin is the pigment that is responsible for skin’s color and is produced within cells called melanocytes. Depending on skin tone, discolored patches will be pink, tan, brown, dark brown or purple.

There are several other forms of hyperpigmentation such as photodamage, also known as sun, age or liver spots which develop due to unprotected sun exposure. Skin conditions such as  melasma appear as grayish-brown patches and are triggered by hormonal changes and worsened by sun exposure.

In short, the difference between hyperpigmentation caused by acne, and other types of hyperpigmentation is that the former is a response to inflammation.

Postinflammatory hyperpigmentation vs. acne scars

While both PIH and acne scars can develop after acne lesions heal, they are two separate skin concerns that require distinct treatments.

Acne scars

Acne scars fall into two basic groups: atrophic (depressed) and hypertrophic (raised). They develop during the healing process and result from a degradation of collagen fibers and subcutaneous fat; and when an overabundance of collagen is produced, respectively.

There are a number of acne grading systems that categorize and assign a grade based on severity and clinical features. These range from macular which are mild, red and flat to severe and deeply pitted or raised.  

Acne scars can fade with time but they will not completely resolve on their own; professional treatments are required and include microneedling, lasers, chemical peels and dermal fillers.

Postinflammatory hyperpigmentation

PIH refers to discolored marks that remain when acne lesions heal; they are neither raised nor flat and can be tan, brown, purple or blue-gray depending on skin color.

Hyperpigmented skin can fade with time but is most likely to be permanent. First steps include targeting the inflammation brought on by acne to halt the progression of inflammation and consistent use of sunscreen as a preventative.

First-line treatment is a skin-lightening topical for mild cases followed by second-line or combination microdermabrasion, chemical peels or laser therapy for severe or difficult-to-treat cases. Treatment typically lasts months to years as progress is typically slow.

Skin of color is particularly susceptible to PIH as this group has elevated levels of melanin in their skin resulting in a far higher severity and incidence. As well, they are more likely to develop acne, which adds an additional burden. 

Why acne is more prevalent among this group has been studied. Bacteria levels, as well as sebaceous gland activity have been studied and compared to that of Caucasian data, but the results have been inconclusive or contradictory.  

Hyperpigmentation is one of the most common complaints among people of color.

Topical Treatments for Hyperpigmentation Caused by Acne

Treatment of PIH usually involves a lengthy timeline that can take up to 1 year or even longer. While there are several topical treatments available, hydroquinone and retinoids appear to be the most effective, especially when used together in combination therapy.

Hydroquinone 

Hydroquinone is a topical skin-lightening agent that is available in gel, ointment or cream formulas for overall use or as a spot treatment. It is considered the gold standard for PIH therapy and works by inhibiting melanin synthesis. It is available over the counter and in prescription strength for more severe cases.

Hydroquinone has a very high systemic absorption rate and several serious side effects, therefore it is used for only several months at a time. In addition, it is advised to wear a broad spectrum sunscreen to avoid the risk of photodamage and because exposure to sunlight could reverse its effects.

This agent is typically used as a first-line treatment or as one part of combination therapy, including a mid-potent steroid to reduce irritation and a retinoid to achieve greater results.

In one study that examined the efficacy and tolerability of a combination hydroquinone and retinol treatment, researchers found a significant reduction in melanin content at week 4. Participants were Fitzpatrick skin types II–VI, indicating they were medium to dark in skin tone.

Retinoids

Topical retinoids are very effective at reducing hyperpigmentation: they block tyrosinase transcription to inhibit melanin synthesis; stimulate skin cell turnover to clear clogged pores of excess oil, debris and bacteria; and prompt skin to shed. This activity also enables better penetration of topical solutions such as hydroquinone.

Tretinoin is the most potent and best-studied retinoid, and has been shown to be both a preventative and a treatment for pigmentation. Tazarotene and adapalene are other retinoids that work via similar mechanisms.

In one 16-week study of tazarotene 0.1% cream versus adapalene 0.3% gel, both tazarotene 0.1% cream and adapalene 0.3% gel were effective and well tolerated in patients with at least moderate acne. However improvements were significantly greater with tazarotene than adapalene.

Professional treatments can be used as a sole treatment but are typically combined with a topical agent to achieve greater results. Two of the most effective options are microdermabrasion and chemical peels.

Chemical peels

Chemical peels are professional treatments that incorporate an acid solution in various strengths—superficial (or light), medium and deep—to address various skin concerns including aging skin, scars, rough texture and hyperpigmentation. 

Superficial chemical peels are the most appropriate choice for PIH treatment using either glycolic or salicylic acid, or Jessner’s solution. These peels are well tolerated with minimal side effects and work by removing lesions, excess pigment, surface debris and flakiness on the outermost layer of skin. They can also clear pores to reduce the incidence of acne.

Several treatments are required to see noticeable results as they are gradual but cumulative.      

For skin of color, when used with care, a superficial glycolic acid peel is safe and effective, especially when combined with a skin-lightening agent. The best results are achieved with repeated, superficial resurfacing sessions to avoid damaging skin further and increasing pigmentation.

In a comparison of Jessner’s solution peel versus a salicylic acid 30% superficial peel in skin of color, both peels were effective in treating acne lesions as well as PIH. Patients who reported good and very good outcomes were 76.4% and 85.3%, respectively. 

Microdermabrasion

Microdermabrasion uses either a diamond-tipped handpiece or a spray of crystals to gently exfoliate the topmost layer of skin. This not only improves skin tone and texture but as part of the healing process, it boosts collagen production to remodel skin.

It also removes pore-clogging debris and oils, and allows for better absorption of topical treatments. This makes microdermabrasion an effective partner to hydroquinone and retinoids. 

One study group consisting of people with melasma, acne scars, stretch marks and photoaging found that decreased pigmentation and increased collagen density were the most commonly observed changes after 8 treatments.

As with chemical peels, multiple treatments are necessary to achieve optimal results. 

Prevention

There are several measures you can take to prevent or minimize PIH:

  • Apply an SPF30 sunscreen daily; this is essential to prevent the skin from UV rays and is especially important for skin of color
  • Avoid picking and touching your face as this can spread bacteria and cause further inflammation
  • Wash skin gently and avoid exfoliating brushes or scrubbing at the skin
  • Opt for a nonabrasive cleanser that contains an effective acne-fighting ingredient such as benzoyl peroxide
  • Follow your care provider’s instructions and be consistent with acne therapy
  • Choose noncomedogenic products that won’t clog pores and potentially cause breakouts
  • Regularly wash your bedsheets as accumulated dirt and dead skin cells can transfer to your skin, leading to breakouts

Home Remedies 

There are several at-home treatments for hyperpigmentation using ingredients that have been shown to be effective. With that being said, these treatments can’t provide the same results as professional or over-the-counter treatments, especially for medium to severe PIH.

  • Aloe vera has aloin which can break up melanin, and aloesin which prevents melanin formation by inhibiting tyrosinase activity
  • Licorice extract contains glabridin which has been demonstrated to have a skin- lightening effect that is 16 times greater than that of hydroquinone
  • Soy extract has antioxidant and photoprotective properties, and has been proven to be an effective skin-lightening agent 

Takeaway

Postinflammatory hyperpigmentation develops due to skin injury or inflammation and manifests as spots or patches of skin that are darker than that of the surrounding skin.

Both inflammatory and noninflammatory acne are associated with this skin condition as dark spots can form once active lesions heal. They develop as a natural response when the body triggers an overproduction of melanin as part of the healing process. Those with skin of color have greater amounts of melanin in their skin and are therefore at greater risk. 

Both topical and professional treatments are effective in fading pigmented skin, and studies have shown that it is the combination of the two that produces greater results.

Treatments effectively work through different modes of action to exfoliate dead skin cells, debris and excess oils from pores, inhibit melanin synthesis and stimulate collagen production.

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