Lentigo (Liver Spots)

Lentigo is the term for light brown or dark spots on the skin, which are sometimes also referred to as liver spots. Lentigines refer to more than one spot. These spots can show up slowly over time or suddenly. Solar lentigo and lentigo simplex are harmless. However, lentigo maligna (LM) is a precancerous spot that can lead to melanoma (skin cancer). A few differences in the characteristics of these spots can help you tell the difference between the types. 

Always see a dermatologist (a medical doctor who specializes in skin conditions) yearly—or sooner if you are unsure about an area on your skin. They can use specific tools to rule out harmful skin conditions and give you options for over-the-counter (OTC) or prescription treatments when necessary.

Types of Liver Spots

Common types of lentigo include solar lentigo and lentigo simplex.

• Lentigo simplex: Also known as simple lentigo, this is the most common type. It's present at birth or during childhood.
• Solar lentigo: Also known as age spots, liver spots, and ink spots, this occurs with age and sun exposure.
  
• Lentigo maligna (LM): LM is a separate condition from solar lentigo or lentigo simplex. It is precancerous and can turn into melanoma (a type of skin cancer). 

Lentigo Symptoms 

Solar lentigines typically occur where you’ve had the most sun exposure, such as on your arms, face, hands, and neck. However, they can also occur in other areas. They may increase in number with age, get darker in the sun, and don’t typically fade in the winter. 

Lentigo simplex may be present at birth or occur during childhood. Lentigines can appear anywhere on your body, regardless of sun exposure. 

Other lentigo characteristics include:

• Clear margins (edges are not blurry, jagged, or notched)
• Even color 
• Flat, oval shape
• Painless
• May look like inkspots
• Stays a fairly consistent size
• Tan to dark brown color

It can be challenging to distinguish harmless solar lentigo from lentigo maligna initially. However, if LM progresses to lentigo maligna melanoma (LMM), the spot may:

• Have fuzzy borders
• Feel raised rather than flat
• Invade surrounding structures like hair follicles
• Mimic scar tissue
• Cause discomfort, itching, or bleeding
  

What Causes Lentigo? 

Solar lentigines form with prolonged exposure to ultraviolet (UV) light from sunlight, tanning beds, medical radiation treatment, or UV therapy. This triggers your body to produce excess melanin (the pigment that gives skin its color), forming dark spots.

Sun exposure does not cause simple lentigo, but the exact cause is unclear. It sometimes occurs with certain genetic conditions.

Risk Factors

Solar lentigo can affect anyone. However, the following factors increase your risk.

• Fair skin
• Older age 
• Sunburns
• Radiation therapy
• Frequent exposure to sunlight or tanning beds
  
• Psoralen (an oral medication used to treat certain skin conditions) plus ultraviolet A (PUVA) therapy

Diagnosis

To diagnose lentigo, a dermatologist will check the appearance of the spots. They will ask about your medical history, family history, risk factors, and additional symptoms. The provider will aim to differentiate lentigines from other skin conditions, including skin cancer. 

The ABCDE Approach

The ABCDE approach helps evaluate skin spots. The following characteristics typically indicate a more serious skin condition, such as skin cancer:

• Asymmetry (A): Uneven shape
• Border (B): Irregular, jagged, blurry, or poorly defined edges
• Color (C): Uneven coloring with multiple shades of brown, black, blue, red, or white
• Diameter (D): Typically larger than 6 millimeters (mm)—about the size of a pencil eraser—but can be smaller
• Evolution or Elevation (E): May change in size, shape, color, texture, or elevation

Tools and Tests

Providers also commonly use diagnostic tools and tests to distinguish harmless spots from precancerous or cancerous areas. These include:

• Dermoscopy: A handheld dermatoscope allows providers to visualize structures within the skin and identify irregularities.
• Skin biopsy: The provider sends small skin samples to a laboratory for microscopic examination. 
• Wood's lamp examination: The provider uses UV light to detect certain skin conditions by highlighting fluorescence patterns.
• Reflectance confocal microscopy (RCM): The provider uses a non-invasive imaging tool with laser light to examine skin cells.

Stages of Lentigo Maligna Melanoma

Solar lentigines and lentigo simplex do not have stages. However, you may experience the darkening of existing age spots or the development of new spots.

Lentigo maligna is precancerous in the in situ stage, meaning it's limited to the top layer of skin. If it becomes melanoma, it is in the invasive stage, meaning it spreads into deeper layers of the skin.

Treating Liver Spots

Solar lentigo and lentigo simplex do require medical treatment. However, some people wish to conceal it with makeup or use topical (on the skin) over-the-counter (OTC) or prescription treatments. A dermatologist may also suggest medical procedures like laser therapy.

Some treatments can cause redness, irritation, or peeling. They usually take time and multiple sessions to work.

Over-The-Counter (OTC) Creams

Before trying topical treatments, perform a patch test. Put a small amount of a product on your skin to see if it causes any irritation or allergic reactions. Wait a day or two before using it more widely. 

In addition to using sunscreen with SPF 30 or higher to keep spots from getting darker, you can try lightening serums, creams, or gels. OTC skincare products typically contain ingredients such as:

• Alpha hydroxy acids: Chemicals that help you shed dark skin cells, like glycolic acid
• Retinoids: Vitamin A products like retinol
• Vitamin C: For example, tetrahexyldecyl ascorbate
• Kojic acid: Fermented rice wine that helps reduce the production of melanin
• Lotus sprout extract: Liquid from young lotus plants
• Hydroquinone: A bleaching agent

Prescription Medications

A dermatologist may prescribe topical treatments if OTC treatments don't work. Some prescriptions have the same ingredients as OTC treatments but typically involve higher strengths or concentrations. Prescription ingredients usually include: 

• Hydroquinone
• Retinoids
• Azelaic acid (a natural compound that reduces melanin production)
• Cysteamine (a substance that inhibits melanin production)

Procedures

A licensed esthetician typically performs certain procedures in a dermatology office. The techniques may differ, but each one aims to destroy the excess melanocytes responsible for the dark pigmentation of the spots and promote the growth of new, lighter skin cells. Possible procedures include: 

• Cryotherapy: Freezing using liquid nitrogen
• Intense pulsed light (IPL) therapy: Broad-spectrum light
• Laser therapy: Focused beams of light
• Chemical peels: Chemical solutions that exfoliate the top layer of skin
• Dermabrasion: A rotating instrument with texture that exfoliates

Prevention

Preventing UV damage helps reduce the risk of lentigo and decrease the darkness of current spots. This includes limiting sun exposure during peak hours (10 am-3 pm), wearing protective clothing and sunglasses, regularly applying sunscreen, and avoiding tanning beds. 

Related Conditions 

Actinic keratosis (rough patches from sun exposure) and seborrheic keratosis (waxy, raised spots with a warty surface) can resemble lentigo. Underlying health conditions, like Addison's disease (when the body doesn't make enough cortisol hormone) and vitamin B12 deficiency, can also lead to lentigo. 

Lentigines can appear with rare genetic syndromes. For example, Peutz-Jeghers syndrome (PJS) can cause lentigines on the lips, palms, and soles. Other examples of these rare genetic syndromes include:

• Inherited patterned lentiginosis
• Carney complex
• LEOPARD syndrome
• Laugier-Hunziker syndromes

Psoralen plus ultraviolet A (PUVA) therapy, a treatment for skin conditions like eczema (red, itchy, swollen skin patches) or psoriasis (thick, scaly patches), can cause lentigines. Psoralen plus ultraviolet A (PUVA) therapy combines psoralen (a chemical that makes the skin more sensitive to light) and UV light. 

Living With Lentigo

Solar lentigo and simple lentigo are harmless and don't need treatment. However, lentigo maligna (LM) can progress to lentigo maligna melanoma (LMM). If you're unsure about a spot, consult a healthcare provider to confirm if it's lentigo and not another skin condition.

You can prevent lentigo by protecting your skin from UV exposure. You can also consider OTC creams, prescription topical treatments, and cosmetic procedures like laser therapy or chemical peels.