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Hyperpigmentation, or skin darkening, is not harmful to health. However, it's one of the most common reasons people visit dermatologists. This condition happens when the skin makes too much melanin, causing dark patches. It can be triggered by things like sun exposure, hormonal changes, certain medications, or skin injuries like acne or burns.
In this blog, we’ll explore the types of hyperpigmentation, what causes them, how deep they are in the skin, and whether they’re permanent. You’ll also learn about treatment options and tips to reduce and prevent unwanted dark spots for a more even skin tone. Keep reading to find out more!
Quick Summary
1. Melasma: Hormonal skin darkening, often recurring with sun exposure or hormonal changes.
2. Post-inflammatory Hyperpigmentation (PIH): Dark spots caused by skin inflammation or trauma, usually fades but can be recurrent.
3. Freckles (Ephelides): Genetic light brown spots that persist but may lighten in winter or with age.
4. Lentigines: Permanent age or sun spots that increase with age and sun exposure.
5. Drug-induced Hyperpigmentation: Skin discoloration from medication, may fade after discontinuation.
6. Café-au-lait Spots: Congenital light brown patches, permanent but benign.
7. Naevus of Ota/Ito: Permanent blue-brown pigmentation with potential age or hormonal intensity shifts.
8. Exogenous Ochronosis: Permanent bluish pigmentation caused by prolonged use of high-concentration hydroquinone.
9. Mechanical Discoloration: Darkened skin from friction or trauma, typically reversible with care.
10. Physiological Pigmented Lines (PDLs): Genetic linear pigmentation variations, permanent but harmless.
Freckles
Freckles are small, light brown or brown spots on the skin. They are commonly found on the face and arms, areas exposed to sunlight. Histologically, they are located in the basal layer of the epidermis.
Freckles are a genetically inherited condition, so they are often seen in family members. Freckles appear most frequently in people with fair skin and red hair. These spots persist throughout life but are less severe in winter and with age.
Cause: Genetic
Depth: Epidermal
Is Permanent? Yes, they remain present throughout life but can lighten in winter and with age.
Treatment: Acid and chemical peel products containing alpha hydroxy acid, trichloracetic acid, glycolic acid or phenol, retinoids, retinols, Laser and Cryotherapy can help in lightening freckles.
!!! Your dermatologist will discuss the best treatment options for you if you wish to fade your freckles !!!
Chloasma
Chloasma, also known as melasma or the "pregnancy mask," is a common skin lesion. It affects women more than men. It is characterized by symmetrically distributed, irregular yellow-brown or dark brown lesions. These lesions often appear on the face but can also affect the neck, chest, arms, and forearms. (Images)
Chloasma occurs in three patterns:
1. Mid-facial pattern: Found on the nose, forehead, and above the upper lip. This pattern accounts for 50–80% of cases.
2. Malar pattern: Found on the cheeks.
3. Mandibular pattern: Found on the mandible and chin.
Main contributor is solar radiation, which intensifies symptoms and causes relapses. Other contributors include oestrogen, progestogens (two hormones that influence pigmentation), and genetic predisposition. Hormonal influences make chloasma more common during pregnancy or when taking oral contraceptives.
Cause: Hormonal
Is Permanent? Melasma is often described as recurrent, with sun exposure and hormonal changes triggering relapses. Complete removal may not be possible, though treatments can manage its appearance.
Café-au-lait Spots
Café-au-lait spots are light brown, oval-shaped discolorations with well-defined edges. These spots are not influenced by sun exposure and are located in the basal layer of the skin. Their size and number can vary.
In 10–15% of healthy people, these spots appear as single lesions. When in larger numbers (Usually more than 5 spots), with a diameter of over 5 mm, they may indicate neurofibromatosis, a genetic disorder that causes tumors to form on nerve tissue.
Cause: Sun Exposure
Depth: basal layer of the skin
Is Permanent? Café-au-lait spots are congenital and do not fade over time, though their significance depends on their number and size (e.g., indicating neurofibromatosis if numerous).
Treatment: Café-au-lait spots don't need treatment since they are benign (noncancerous) and do not cause symptoms. If you want to remove your café-au-lait spots for cosmetic reasons, talk to your healthcare provider about laser treatment.
Lentigines
Lentigines are called age spots or sun spots. These lesions range from light brown to black. They vary in shape and size, typically measuring 3–12 mm but can be larger. These spots are located in the basal layer of the epidermis. They are permanent and do not disappear on their own.
Lentigines usually develop after the age of 40–50 and become larger and more numerous with age. People who frequently use solariums or tanning beds may develop them earlier.
Lentigines typically appear on areas exposed to sunlight for many years, such as the backs of the hands, forearms, face, and forehead. In men, they often occur on the scalp (in balding areas) and around the neck.
They are mainly an aesthetic problem, but attention should be paid to the diagnosis of malignant lentigines or melanoma.
Cause: Sun Exposure
Depth: Basal layer of the epidermis
Is Permanent? Some types of lentigo can disappear on their own over time, but most don't go away. Other types can only be removed with treatment.
Treatment: Although lentigo spots are often caused by sun damage to your skin, they're not cancerous or harmful and don't require treatment.
PDLs
PDLs are also called Voigt lines or Futcher lines. They are sudden changes in skin color from lighter to darker in a linear pattern. PDLs are most often seen on the limbs, trunk, and face. These marks usually show up during childhood or puberty and last throughout life.
Melasma and post-inflammatory hyperpigmentation on the face should be differentiated from facial PDLs. PDLs are harmless variations in skin color. They commonly affect Black women during pregnancy. The exact cause of PDLs is still unknown, but research on this condition is growing.
PDLs are benign pigmentation variations that appear during childhood or puberty and last for life. Some PDLs triggered during pregnancy may regress on their own after childbirth.
Cause: Genetic
Is Permanent? PDLs during pregnancy often fade naturally after childbirth. They do not usually need treatment.
Ochronosis
Ochronosis is a condition where people develop small, speckled blue-black spots with a grayish-blue color, usually over the malar, temple, and cheek regions. Although it's rare, certain factors can increase the risk. These include being female, having a skin discoloration condition like melasma or post-inflammatory hyperpigmentation (PIH). Research has shown that using products with high concentrations of hydroquinone, especially above 4%, increases the chance of developing ochronosis. Some studies in Asia have also found a link between these products and the condition.
Cause: Prolonged use of hydroquinone above 4%, melasma, or post-inflammatory hyperpigmentation.
Depth: Dermis (affecting the deeper layer of the skin).
Is Permanent? Yes, it is typically a chronic and permanent condition.
Treatment: Not specified, but prevention involves avoiding high-concentration hydroquinone products.
Post-inflammatory Hyperpigmentation (Secondary Discoloration)
Post-inflammatory discoloration appears as dark spots of various shapes and sizes. These dark spots develop after acute or chronic inflammation has resolved. They can affect people of all ages and races, but individuals with darker skin are more prone to them.
This type of discoloration occurs because inflammation or skin trauma triggers melanin production and is typically located on the dermis surface. Acne is one of the most common causes of post-inflammatory discoloration. Other causes include:
- · Lichen planus: A chronic inflammatory skin condition causing purple, itchy bumps, often on the wrists, ankles, and other areas.
- · Atopic dermatitis: A long-lasting skin condition marked by dry, itchy patches, often linked to allergies and asthma.
- · Allergic contact dermatitis: A skin reaction resulting from exposure to allergens or irritants, causing redness, swelling, and itching.
- · UV and ionizing radiation: Types of radiation that can damage skin cells, leading to sunburn, premature aging, or skin cancer.
In most cases, these spots gradually fade over time. Successful treatment should address the underlying condition or factor causing the discoloration.
Cause: Secondary (Inflammation or skin trauma triggering melanin production).
Depth: Basal layer of the epidermis; PIH also representing the epidermal and dermal patterns.
Is Permanent? No, Resolution Time: PIH often resolves, but it may take months to years to clear completely. It is mentioned that some cases are recurrent if the underlying cause (e.g., inflammation) persists or is not treated.
Treatment: Address the underlying condition, such as acne, dermatitis, or UV exposure.
Mechanical Discoloration
Mechanical discoloration results from long-term exposure to factors causing mechanical trauma. The injury leads to over production of melanin and pigment release.
Examples of mechanical trauma include friction from tight clothing, shoes, or excessive rubbing, which can cause localized areas of skin irritation. Pressure from constant use of body parts or equipment, such as knee pads or shoulder straps, can also result in pigmentation changes. Scratching or repetitive injury, such as from insect bites or skin conditions like eczema, may lead to darkened spots or hyperpigmentation.
Lastly, PIH can be iatrogenic from chemical and mechanical resurfacing procedures such as medium-depth and deep chemical peels, especially in patients with Fitzpatrick phototypes III through VI, sclerotherapy, microdermabrasion, and microneedling.
For example, microneedling causes controlled physical trauma to the skin, inducing a beneficial wound healing cascade.
Cause: Long-term mechanical trauma, such as friction, pressure, or repetitive injury.
Depth: Epidermis and sometimes dermis, depending on the severity of trauma.
Is Permanent? No, typically reversible, but persistent trauma can prolong discoloration.
Treatment: Minimize mechanical trauma, avoid irritants, and manage with appropriate skin care or medical treatments.
Drug-Induced Discoloration
Drug-induced discoloration includes a variety of skin changes that differ in color, location, and intensity. These discolorations are not always caused solely by increased melanin. Drug metabolites often accumulate in the skin and cause these changes.
Solar radiation plays a significant role in drug-induced discoloration. The condition is more common in areas exposed to sunlight, especially when using photosensitizing medications. These medications are often used to treat conditions like infections, inflammation, or acne.
Cause: Drug metabolites accumulating in the skin, often exacerbated by solar radiation and photosensitizing medications.
Depth: Epidermis or dermis, depending on the drug and extent of deposition.
Is Permanent? Hyperpigmentation triggered by incorrect or overuse of treatments is potentially temporary.
Treatment: Discontinue the causative medication and use targeted treatments to reduce discoloration.