Hyperpigmentation Causes: Common Causes, Medical Conditions, and More

• Hyperpigmentation refers to patches of skin that are darker than the surrounding area
• Sun exposure and inflammation are the leading causes
• Darker skin tones are most affected by hyperpigmentation
• Several treatments are available and will depend upon cause and skin tone 

Hyperpigmentation is a very common and usually harmless skin condition that describes small and large dark patches of skin. Hyperpigmentation causes are many and include such factors as overexposure to the sun, aging and hormonal fluctuations. In some cases it can signal a more serious underlying medical condition. 

What Is Hyperpigmentation?

Hyperpigmentation occurs when the skin overproduces melanocytes, melanin-producing cells responsible for giving skin its color. This results in spots or patches that are darker than the surrounding skin. 

There are several types of hyperpigmentation, with the most common being melasma, solar lentigo and postinflammatory hyperpigmentation (PIH).

Common Causes of Hyperpigmentation 

Several causes can trigger the development of hyperpigmentation: hormonal fluctuations, sun exposure, inflammation and melasma are among the most common. 

Medications 

Specific medications that have been identified as causing hyperpigmentation include: nonsteroidal anti-inflammatory agents (NSAIDS) antibiotics, antiarrhythmics, antipsychotics and anticonvulsants. Antipsychotic medications are known to cause blue-gray pigmentation in areas of sun-exposed skin.

With drug initiation, discolored skin slowly develops and spreads over the course of months or years of treatment. Most often, the discoloration can be reversed once the drug is discontinued.

This type of hyperpigmentation is called medication-induced cutaneous pigmentation (MIP) which has been estimated to account for 20% of all pigmentation cases. Possible causes include an accumulation of pigmentation in the skin triggered by the drug, drug-induced inflammation and an accumulation of heavy metals. 

This condition can be worsened by sun exposure. 

Postinflammatory hyperpigmentation

Postinflammatory hyperpigmentation (PIH) refers to the darkening of the skin following a skin injury. There are a wide range of circumstances that can cause these pigment changes including skin disorders such as acne, psoriasis, atopic dermatitis; irritants, burns; insect bites or allergic reactions.

During the wound-healing process, inflammation occurs which drives melanin production. The result is the formation of dark spots in place of the skin injury. 

This is especially true for those with darker skin tones, and occurs with greater frequency and severity. This is due to the greater levels of pigment in darker skin. 

Sun exposure 

The sun is by far the most common cause of hyperpigmentation. Solar lentigos, (also referred to as sun spots, liver spots or age spots) results from prolonged exposure to the sun’s damaging UV rays and is a sign of photodamage.  

Dark spots can develop on any part of the body but most typically develop on skin that is most exposed to the sun such as the face, neck, shoulders and hands.

Harmful UV rays accelerate the production of melanin as a means of protecting the skin from damage. This damage occurs not only on the surface of skin but deeper within the dermis becoming more visible with age and continued sun exposure. 

One study examining solar lentigos determined that both chronic and acute sun exposure contribute to the development of hyperpigmentation.

Medical Conditions That Cause Hyperpigmentation

Hyperpigmentation can be brought on by a variety of medical conditions, including:

Addison’s disease

Addison’s disease is a rare disorder in which the body is unable to produce adequate amounts of two critical hormones.

As Addison’s disease progresses, the adrenal glands produce less cortisol and aldosterone, which causes the pituitary gland to overcompensate and make more melanocyte-stimulating hormones (MSHs). This overstimulation of MSH leads to an increase in melanin production, which results in a darkening of the skin.

One of the first signs of this disease is not only topical pigmentation but oral pigmentation as well. Hyperpigmentation can be limited to black freckles on the forehead, face and shoulders, but widespread areas of hyperpigmentation are common, described as a bronzing effect. 

Hemochromatosis

Hemochromatosis is the most common single gene disorder in the native Caucasian population of the United States, and is characterized by enhanced intestinal absorption of iron, resulting in iron overload. This disorder is triggered by heredity and environmental factors.

An excess of iron promotes oxidation and an increase in melanocytes. In the early years of this disease, skin appears sunburned and then gradually deteriorates to a bluish-gray or bronze hyperpigmentation.

Melasma

Melasma is an inherited condition that is more common among women of color due to the greater presence of melanocytes. This skin condition develops when elevated levels of the hormones estrogen and progesterone stimulate melanin overproduction. The resulting hyperpigmentation can worsen when unprotected skin is exposed to the sun.

This form of hyperpigmentation is often referred to as the mask of pregnancy due to the dark patches that develop on the forehead, cheeks, nose and chin. 

While it’s cause is not fully understood, some triggers have been identified to include sun exposure, pregnancy, birth control pills and steroids.

Causes of Hyperpigmentation in Dark and Light Skin Tones

Both dark and light skin tones are susceptible to the same causes of hyperpigmentation, however with skin of color, the dark spots are more severe and longer lasting. 

Skin color is based on both the number of melanin-producing melanocytes and their distribution: Black skin will have the most, Caucasian the least and Asian skin will be in between. 

People with darker skin are naturally more prone to hyperpigmentation due to this higher baseline of melanin content; lighter skin tones are more susceptible to hyperpigmentation due to sun damage.

Best Treatments for Hyperpigmentation  

There are several treatments available to reduce the appearance of hyperpigmentation, and they are typically chosen based on skin tone and cause. Skin of color is the most challenging to treat; while some skin conditions such as melasma can resolve naturally.

Chemical peels

Chemical peels use agents such as glycolic or salicylic acid to address hyperpigmentation via controlled injury to the outer layers of skin. This exfoliates the top layers of skin and allows fresh skin cells to replace damaged ones. 

Some chemical peels are available over the counter, but professional in-office treatments will provide the most immediate and pronounced results.

Chemical peels are safe and effective for lighter skin tones and can be applied to all types of hyperpigmentation, with melasma and sunspots being the most receptive to these treatments.

For darker skin tones, lighter chemical peels can be safely used alongside other treatments. Glycolic and lactic acid have been proven to be the best options in terms of both safety and efficacy. 

Dermabrasion

Dermabrasion is a minimally invasive in-office procedure for skin resurfacing. A specialized rotating device removes the outer layers of damaged skin which effectively reduces the appearance of all types of dark spots. When skin regenerates, a new layer of skin forms that is significantly smoother and clearer.

Dermabrasion is not an appropriate method for darker skin, as it could result in scarring or increased pigmentation. 

Lasers

Lasers are also effective platforms for skin resurfacing; they use light energy and heat to even color and tone, and smooth texture. There are two types of lasers that can effectively treat hyperpigmentation: ablative and nonablative lasers. 

Ablative lasers remove the top layers of skin to prompt skin cell renewal and boost collagen production. Skin will appear smoother, tighter and more even-toned. These treatments require significant downtime but the results are typically dramatic. 

Nonablative laser treatments are less aggressive than ablative as they heat up the underlying surface but leave the skin intact. As such they have been determined to be a safe and effective option for skin of color.   

Microdermabrasion

Similar to dermabrasion, microdermabrasion is a less aggressive alternative that is suitable for all skin types and tones. 

With this treatment, a diamond-tipped handpiece or a spray of fine crystals gently exfoliates the top layers of skin rendering it smoother and less pigmented. Typically, several sessions are  required to achieve best results.

One study had patients subjected to 8 microdermabrasion sessions scheduled 1 week apart. Of all the improvements to skin, they found a decrease in pigmentation and an increase in collagen as the two most observed changes.  

Skin lightening creams

There are many skin lightening creams available both over the counter and by prescription. These contain a lightening agent such as hydroquinone, niacinamide, N-acetyl glucosamine,  kojic acid or licorice root extract.  

While hydroquinone has long been the gold standard in skin lightening, there is controversy surrounding its use as its safety has been questioned. In light of this, it is important to speak with your doctor before using it. This ingredient is not recommended for darker skin tones as it can worsen existing hyperpigmentation. 

When purchasing a skin lightening cream, ensure you obtain it from a trusted source and read the product label carefully.  

Compared to professional treatments, skin lightening creams will take longer to produce results and may not be as effective.    

Takeaway

Hyperpigmentation is a common skin complaint that affects all skin types and tones. Many factors can lead to dark spots developing on skin, especially sun exposure and inflammation.

Some forms of hyperpigmentation, such as melasma, will eventually resolve naturally, while others will require professional treatments. Darker skin tones are more susceptible to hyperpigmentation due to the higher level of melanin present in the skin.

There are several effective treatments available to resurface the top layer of skin and reduce or eliminate discolored areas. Professional treatments provide an added benefit of strengthening the skin by stimulating collagen production.