Freckles manifest as asymptomatic small, circular, brownish macules, 2 to 3 mm in diameter which start appearing early in life on the face, dorsal aspects of the hands and extensors of the forearms, and keep on increasing in number as the age advances.
They may appear in people as young as 1 or 2 years of age.
Most freckles are generally uniform in color but can vary somewhat in color — they may be reddish, yellow, tan, light brown, brown, or black.
They are produced by exposure to ultraviolet light and typically fade in the winter. Continued exposure to sunlight leads to the appearance of new lesions and darkening of the old ones.
This disease is inherited as an autosomal dominant character and depends upon the presence of an abnormally large amount of melanin in the epidermis.
They are quite common, and rarely develop into skin cancer.
Some people are more likely to get freckles than others, depending on their genes and skin type. If a person is genetically more likely to develop freckles, exposure to sunlight can make them appear.
Freckles are common in children and may disappear or become less noticeable as they grow up.
Ephelides is the medical term used for freckles. Although ephelides are predominantly benign, they may be seen in association with systemic diseases like as xeroderma pigmentosum and neurofibromatosis.
People of Caucasian and Asian descent are more prone to ephelides.
Pathophysiology and Causes
Freckles are macule [flat, non-raised lesion] that appear when melanin, the skin pigment, builds up under the skin. Freckles may vary in coloration and look brown, red, or tan.
These are light initially but with sun exposure can turn dark.
In genetically susceptible individuals, there may be somatic mutations in epidermal melanocytes which causes increased pigment formation.
The number of melanocytes is not increased and this differentiates freckles [ephelides] from lentigines where they are increased.
Thus sun exposure [UV-A and UV-B light exposure] leads to large melanosomes and increased melanin production and there lies the reason why the lesions appear after sun exposure.
Ephelides can be inherited as an autosomal dominant trait, and first-degree relatives are at higher risk. These are more common in people with fair skin and/or with blond or red hair.
Melanocortin 1 receptor (MC1R) gene polymorphisms is thought to be associated.
Skin can produce two types of melanin called eumelanin and pheomelanin. While the former is protective against UV rays, the latter is not.
People who usually produce mostly eumelanin [dark hair, eyes, and skin] are less likely to develop freckles.
People who produce mainly pheomelanin [red, blonde, or light brown hair, light-colored skin, and eyes] are more likely to develop freckles.
Sunlight exposure to both UV-A and UV-B radiation in susceptible individuals induces freckles by stimulating melanocytes to produce melanin.
- Freckles in xeroderma pigmentosum can occur even in dark in heterozygous carriers with this autosomal recessive disease.
- Neurofibromatosis is an autosomal dominant condition that may have freckles in the folded regions.
Lesions Similar to Freckles
The list includes solar lentigines or sun spots, melasma and mole.
Read more about melasma.
Here are the differentiating features of freckles, sunspots, and moles.
Freckles vs Sunspots (Solar Lentigines, Age Spots, old age spots, Liver Spots)
Lentigines can have many causes. They are also called sunspots or age spots or liver spots. They are called liver spots because once they were thought to be caused by liver diseases.
Lentigines are also called senile-freckles.
A lentigo is a small, sharply circumscribed, pigmented macule surrounded by normal-appearing skin. There could be hyperplasia of the epidermis and increased pigmentation of the basal layer.
The melanocytes are increased in number [compare with freckles].
Solar lentigines are caused by increased exposure to the sun over a period and lentigines may evolve slowly over years, or erupt suddenly. The color ranges from brown to black.
Pigmentation may be homogeneous or variegated, with a color ranging from brown to black.
Solar lentigines develop during adulthood usually in Caucasians and adults over 40 years old.
Secondly, the freckles will increase in number and darkness with sunlight exposure, whereas lentigines will stay stable.
Lentigens are also common in sun-exposed areas.
Freckles Versus Moles
Moles are dark skin lesions, flat or raised and not necessarily associated with sun exposure. They are more common in light skin people too.
Mole is normally present at or soon after birth but can appear later too. It is made of the pigment-forming cells with abundant vascular supply. The color may range from brown to pink. The shapes can vary.
A mole will normally increase in size with the growth of a person.
There is no relation to sun-exposure and moles can be found anywhere on the body.
The size is usually less than 6 mm.
The risk of melanoma, a type of skin cancer increases with the number of moles.
- Malignant Melanoma
- Seborrheic Keratosis
- Xeroderma Pigmentosum
Lab and imaging studies are not necessary for ephelides. Biopsy is rarely required but may be done for definitive diagnosis in certain cases where the larger melanocytes without an increase in number would confirm the diagnosis.
Solar lentigines have an increased number of melanocytes in the basal cell layer, in contrast.
Treatment of Freckles
Treatment is not required for ephelides (freckles).
Sunscreens may be used to prevent enhancement of the freckling caused by sun exposure.
If desired, chemical peels, cryotherapy, and laser treatment may be attempted to make ephelides less pronounced.
Products containing trichloroacetic acid and phenol are effective in lightening freckles.
Other compounds that may help include:
- alpha hydroxy acids
- azelaic acid
- vitamin C
Prevention of Freckles
Protection from sun exposure [ultraviolet light exposure] reduces the chance of developing new freckles.
Following recommendations are given for protection from sunlight
- Water resistant
- UVA and UVB protection
- SPF of 30 or higher
- Reapply after every two hours when swimming or sweating
- Protective clothing
- Wide-brimmed hat
- Prefer shading for work
- Avoidance of peak sun hours