Freckles are small brown spots on your skin, often in areas that get sun exposure. In most cases, freckles are harmless. They form as a result of overproduction of melanin, which is responsible for skin and hair color (pigmentation). Overall, freckles come from ultraviolet (UV) radiation stimulation.

There are two categories of freckles: ephelides and solar lentigines. Ephelides are the common type most people think of as freckles. Solar lentigines are dark patches of skin that develop during adulthood. This includes freckles, aging spots, and sunspots. The two types of freckles can look similar but differ in other ways such as their development.

Ephelides: These freckles form as a result of sun exposure and sunburns. They can appear on anyone who doesn’t protect themselves from UV rays. They show up on your face, the back of your hands, and upper body. This type tends to be most common amongst people with lighter skin tones and hair color. People of Caucasian and Asian descent are more prone to ephelides.

Solar letigines: Like ephelides, this type tends to appear in Caucasians and adults over 40 years old.

The credit for freckles goes to both the natural environment and genetics. Take the quiz below to see if you’re more likely to experience sunburns. Your risk for burning can increase the incidence of freckles.

In a study of 523 middle-aged French women, two elements predicted the presence of freckles: frequent sunburns and a gene known as MC1R, which provides instructions for making melanin. But the gene doesn’t affect all individuals the same way. There are two type of melanin: pheomelanin and eumelanin.

People whose skin produces pheomalanin aren’t protected from UV radiation and tend to have:

  • red or blonde hair
  • light skin
  • freckles
  • skin that tans poorly

People with more eumelanin tend to be protected from skin damage by UV and have:

  • brown or black hair
  • darker skin
  • skin that tans easily

Solar lentigines

For solar lentigines, the French study also found that several different factors increased the likelihood, including:

  • dark skin
  • the capacity to tan
  • a history of freckles
  • sun exposure
  • hormone treatment, such as oral birth control

All freckles fall into the ephelides and solar lentigines category, although freckles and sun spots can differ. Solar lentigines include sunspots, which can sometimes be scaly.

EphelidesSolar lentigines
Originsun exposure and genetic makeupprimarily result of sun exposure
Appearancefirst visible at 2 to 3 years of age after sun exposure and fade with ageaccumulate with age, especially after the age of 40, unlikely to fade
Areas affectedappear on the face, neck, chest, and armsmost common in sun-exposed skin, face, hands, forearms, chest, back, and shins
Sun exposureappear mostly in the summer, fade during winterdo not change with the season
Size1 to 2 millimeters, though they can be larger2 millimeters or larger
Border (edge of skin lesion)irregular and well-definedcommonly well-defined
Colorred to light brownlight yellow to dark brown

Moles are not the same as freckles. They are still skin lesions but are often darker and not necessarily associated with sun exposure. Like ephelides though, moles are more common among light-skinned people.

A mole is made of an excess of pigment-forming cells with a greater than average supply of blood vessels. It’s normally present at or soon after birth.

Moles can take on a wide variety of appearances. The color can range from brown to pink and can assume different shapes. On a young person, a harmless mole will keep pace with a person’s growth.

Freckles and moles by themselves pose no threat. But moles can suggest an increased risk for melanoma, or malignant skin cancer.

Do a self-exam to check your freckles and moles for:

  • A – Asymmetry: Draw a line through the middle. If the halves don’t match, it’s asymmetrical.
  • B – Border: Borders of cancerous moles tend to be uneven, notched, or bumpy.
  • C – Color: A variety of colors in a mole is a warning sign.
  • D – Diameter: A mole bigger than 1/4 inch (a pencil tip) may be cancerous.
  • E – Evolving: Report any change in size, shape, color, or elevation to your doctor.

Make an appointment with your doctor or a dermatologist if your freckles, moles, or sunspots display one or more of the above criteria.

Moles can increase risk for skin cancer

The risk of melanoma increases with the number of moles. Someone with 11-25 moles can have a 1.6 times increased risk for melanoma. This can be as high as 100 times more for someone with 100 moles or more.

Other risks for melanoma include:

  • having fair skin
  • red hair and blue eyes
  • a history of non-melanoma skin cancer
  • a history of excessive tanning or sun exposure

In one analysis, the risk of melanoma for white populations was approximately 32 and 20 times higher than people with darker skin. An annual screening is a good idea, if you fall into one of the at-risk categories or develop a new mole.

For people who want to avoid freckles, prevention is key. It’s also possible to prevent freckles while speeding up their disappearance. The American Academy of Dermatology recommends using a water-resistant sunscreen with an SPF of at least 30 on your skin. Wait 15 minutes before heading outdoors for full protection. Do this every day, even in the winter, to prevent further pigmentation.

“You really can’t freckle unless you’ve had sun exposure,” explains Dee Anna Glaser, MD, chair of the department of dermatology at St. Louis University. “Even if you inherit that tendency, if your mom and dad were the most amazing sunscreen advocates and kept you out of the sun, you probably still wouldn’t freckle.”

Over-the-counter prevention

One study reported good results for lightening freckles and skin pigmentation with products such as:

  • alpha hydroxyl acids (8% AHA toner)
  • Trichloracetic acid (TCA)
  • phenol
  • acid peels

You can purchase acid and chemical peels online. The study above reports Jessner Solution as a potential treatment for freckles. Always patch-test to avoid skin irritation, if you are using a facial peel at home. Wash off the peel immediately if your skin starts to burn and do not leave on for longer than instructed.

Laser therapy

Dr. Glaser suggests laser therapy to lighten or remove freckles. “Some fractionated resurfacing lasers can work beautifully not only on the face, but on the chest, or up on the upper shoulders. Another popular target for these lasers is freckles on legs above the knees, where people get sun exposure from boating and similar activities.”

The fractionated lasers resurface by targeting the water that’s inside the skin’s layers. It drills through the layers until it reaches that middle layer of the dermis. This causes the old epidermal pigmented cells to be expelled, and the reaction leads to collagen remodeling and new collagen formation.

Sunspot removal

By comparison, sunspots don’t generally fade with less sun exposure. Instead, they can be treated with:

  • hydroquinone
  • retinoid creams
  • chemical peels
  • cryotherapy
  • laser therapy

There other lasers that target skin pigments. Instead of going through layers of skin, these laser target and destroy the pigmented areas. The pigment-specific lasers work well on sun spots.

Read more: How do mole removals work? »

Freckles and moles almost always are harmless, but may suggest an increased risk of skin cancer. Knowing your risk and particulars of the ABCDE rubric for assessing changes in skin pigmentation will help with identifying any freckles or moles that may be dangerous. Talk to your doctor about your freckles, moles, or sun spots. They’ll be able to help identify spots for you to monitor closely.

Keep reading: How to get rid of freckles »