Acne is the most common skin condition that affects people of all ages. In fact, roughly 80 percent of people ages 11 to 30 have experienced acne of some kind.
This means that many people will also develop dark spots where their acne once was.
This is known as post-inflammatory hyperpigmentation (PIH).
If you struggle with dark brown spots or patches after your acne has cleared, you are not alone.
The American Academy of Dermatology has found that acne PIH can have a negative impact on self-esteem.
Fortunately, there are several treatments and methods to prevent PIH from developing. These are available over-the-counter (OTC) or with the help of a dermatologist.
Acne vulgaris, or more simply acne, is a skin condition that develops when hair follicles are clogged with dead skin cells, bacteria, and/or oil.
It mainly occurs on the face, upper back, shoulders, and chest.
Acne can be caused or worsened by a number of factors, such as hormones, diet, certain medications (testosterone, corticosteroids), and stress.
There are several types of acne that vary in appearance and severity.
Blackheads are clogged pores that are filled with oil and bacteria, and when they are exposed to the air they become dark.
Whiteheads are clogged pores that are closed off from air, making a raised, white bump.
Papules are an early form of pimples that are small, inflamed red bumps on the skin.
When papules are filled with pus (a yellow-white fluid), they are known as pustules.
Cystic acne is the most severe form, and it develops when there is inflammation and bacteria deep inside the hair follicles.
This can lead to even more inflammation and result in large, red boils on the skin’s surface. In some cases, acne cysts may also contain pus.
Hyperpigmentation After Acne
Hyperpigmentation refers to the dark spots that can develop after acne has healed.
These dark spots are caused by special skin cells, known as melanocytes, making too much melanin (the brown pigment that makes our skin tone).
Melanocytes are found in between the outer layer of the skin (the epidermis) and the inner layer of the skin (the dermis).
Post-inflammatory hyperpigmentation (PIH) is a specific type of hyperpigmentation that occurs after skin injuries and inflammation.
Inflamed acne can lead to PIH, but other causes include family history, and using certain skin products or medications.
During PIH, inflammation causes melanocytes to make more melanin than they normally would, which can make areas of the skin a darker brown color.
This inflammation can also affect another type of skin cell that is responsible for making keratin.
These cells are found in the deeper layers of skin, and when they are damaged they release melanin; this creates a blue-gray skin discoloration, which can be permanent.
People with darker skin tones are more commonly affected by PIH. This includes populations such as:
- African Americans
- People of Middle Eastern descent
- Pacific Islanders
- Native Americans
In some cases, acne scarring can also develop after blemishes have healed.
This scarring is also caused by inflammation, which causes the pores to swell and break down the skin. In order to heal this breakdown, the skin creates new collagen; however, this can cause raised scars to form.
PIH is different from acne scarring because PIH is typically a round, flat area of discoloration.
On the other hand, acne scars can be raised bumps or pits on the skin due to skin damage and tissue loss.
Treatments for Post-Inflammatory Hyperpigmentation
Acne can be troublesome, and dark marks that hang around after the blemishes heal can be even worse.
The good news is there are a number of treatment options for every skin color that can help get rid of these spots and also treat your acne.
Topical treatments include ingredients like skin acids to help lighten the skin and even skin tone. Many are available OTC, while others are given as prescription creams or gels by a dermatologist.
Kojic acid treats PIH by stopping skin cells making melanin. It also has antioxidant effects, which can help fight the inflammation that causes hyperpigmentation. Products typically contain 1 to 4 percent kojic acid.
Azelaic acid stops the skin from producing keratin, while killing bacteria that can infect and clog pores.
Ascorbic acid is a compound derived from vitamin C. It stops skin cells from making melanin, and it can also break down the pigment that has already been made. Ascorbic acid also offers anti-inflammatory benefits because it is an antioxidant.
Alpha Hydroxy Acids
Alpha hydroxy acids (AHAs) are a group of skin acids that exfoliate and help remove dead skin cells. They are gentle on the skin and are commonly used in treatments for both acne and PIH. There are several AHAs, including:
- Mandelic acid
- Citric acid
- Lactic acid
- Glycolic acid
- Tartaric acid
Salicylic acid is a common substance found in many acne treatments because it reduces inflammation and can treat hyperpigmentation.
Retinoids are compounds derived from vitamin A that were traditionally used for treating fine lines and wrinkles. However, they have proven to be useful for treating acne and PIH. Retinoids work by exfoliating the skin, helping it get rid of dead cells to make way for new ones.
One retinoid, hydroquinone, has been called the “gold standard treatment for hyperpigmentation.” Others include tretinoin, adapalene and tazarotene, which have all been shown to be effective in treating PIH.
Chemical peels use skin acids to intensely exfoliate the skin, “peeling” away the top layers that are affected by acne and hyperpigmentation. The new skin that heals in place of the removed layers is smoother and lighter in tone.
Depending on how deep the hyperpigmentation is, you can use an OTC chemical peel or get one in a dermatologist’s office. These can be intense treatments and cause skin irritation; in some cases, they can make hyperpigmentation worse, so use caution.
Laser therapy (also known as laser resurfacing) uses intense beams of light to peel away the top layer of skin and remove hyperpigmentation. It can also be used to stimulate the deep layers of skin to make collagen, smoothing the skin and improving tone.
Dermabrasion uses an abrasive brush to gently scrape the layers of skin from the face, leaving room for healthy skin cells to grow. After around 8 weeks, the healed skin will be smoother and lighter. It can take multiple dermabrasion sessions to see results, depending on how dark and deep the hyperpigmentation is.
Taking Care of Your Skin
Many of the treatments used for PIH and other types of hyperpigmentation can make the skin sensitive.
Proper sun protection can help you get the best results from your treatments.
It is important to apply sunscreen with a high SPF to protect your skin from further damage.
UV radiation from the sun can create dark spots known as age spots; it can also make PIH worse. You can also wear protective clothing to limit your sun exposure.
References, Studies and Sources:
- Acne Scars – Cleveland Clinic
- Postinflammatory Hyperpigmentation – The Journal of Clinical and Aesthetic Dermatology
- Acne: Signs and Symptoms – American Academy of Dermatology
- Acne Vulgaris: Diagnosis and Treatment – American Family Physician
- Acne – Mayo Clinic
- Whiteheads – MedlinePlus
- How To Treat Different Types of Acne – American Academy of Dermatology
- Cystic acne – Mayo Clinic
- Skin layers and melanin – Mayo Clinic
- Postinflammatory Hyperpigmentation – StatPearls [Internet]
- Cosmeceuticals for Hyperpigmentation: What is Available? – Journal of Cutaneous and Aesthetic Surgery
- Azelaic Acid Topical – MedlinePlus
- The effect of Vitamin C on melanin pigmentation – A systematic review – Journal of Oral and Maxillofacial Pathology
- Dual Effects of Alpha-Hydroxy Acids on the Skin – Molecules
- Comparative Study for 35% Glycolic Acid, 20% Salicylic Acid–10% Mandelic Acid, and Phytic Acid Combination Peels in the Treatment of Active Acne and Postacne Pigmentation
- Alpha Hydroxy Acids – Food and Drug Administration
- Topical Retinoids for Pigmented Skin – Journal of Drugs in Dermatology
- Chemical peel – Mayo Clinic
- Laser resurfacing – Mayo Clinic
- Dermabrasion – Mayo Clinic
- The Role of Sunscreen in Melasma and Postinflammatory Hyperpigmentation – Indian Journal of Dermatology
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