Freckles, lentigo and spots
Freckles are dark, circular spots on the skin, 5mm in diameter. They are found at the skin level and are most often located on the parts of the body most exposed to the Sun, like the face, shoulders and hands.
They are typical for persons with light complexion, who burn easily and tan very hard in the sunlight. Freckles have a tendency to become darker and more prominent after Sun exposure, and are less noticeable in the winter months.
How do freckles appear?
Freckles appear as a consequence of larger production of the pigment melanin in certain areas, and are not followed by multiplication of pigmented cells – melanocytes. Avoiding and protection from the sunlight and regular use of protection factor creams can prevent or reduce their appearance.
What types of freckles are there?
There are two basic types of freckles – simple freckles and freckles that are a consequence of sunburn.
Simple freckles (Lentigo simplex) are hyperpigmentation that appear on the skin as a genetic predisposition.
Freckles that appear as sunburn (Solar lentigo) are a permanent damage of the skin and are somewhat darker, have irregular edges and can be larger than the diameter of a pencil.
What are “age spots”?
Age spots are darker colored changes in the skin, most often of the hands and the back of the hands, and less often on the face. They represent lentigo type freckles and are most commonly seen on the skin of elderly people who have had long term exposure to the Sun. The skin is somewhat thinned in the area where they appear and they give of a saggy impression.
In older people with lentigo freckles, brownish, elevated lesions covered with crust appear very often and they are called seborrheic keratoses. Seborrheic keratoses are benign skin growths which can look like moles. They are often brown in color, but they can vary from light brown to black. The size also varies from 0,5 to 2,5 cm. Some keratoses begin as lentigo, and then, by gradual elevation and growth they form a seborrheic keratosis.
The main characteristics of seborrheic keratosis is a waxy, greasy look. They look as if they are glued to the skin or as a drop of melted brown candle wax which has fallen on the skin. Seborrheic keratoses appear on the same parts of the skin as freckles. They often appear in areas exposed to the Sun, but they also appear on the protected parts of the skin. In the beginning the phenomena look like small bulges, and then with further development they have a larger, rough, wart-like surface.
Seborrheic keratoses are quite common after the age of 40. In almost every person there are at least a few seborrheic keratoses during their lifetime.
How do freckles develop?
The development of freckles in the skin is a consequence of genetic predisposition and exposure to the Sun. Two people who are equally exposed to the Sun won’t have the same amount of freckles on the skin. Sunlight and artificial lightsources emit ultraviolet UVB rays. After the exposure to the UVB rays the surface area of the skin, the epidermis, thickens and pigment cells, the melanocytes, produce the pigment melanin in larger quantities. This increased production of melanin is in a way skin’s protection from future exposures to the Sun.
Also, the reaction to sunlight is different in people with different skin types. On the skin of albino persons, freckles never appear, due to a genetically conditioned disorder in melanin production. On the other hand, persons with darker tan are relatively less sensitive to Sun exposure then person with lighter skin. However, even the persons with darker tan are not completely resistant to the influence of the Sun, and so in them to, burns can appear after prolonged exposure. Persons with blond or red hair, light eyes and light skin are especially sensitive to harmful influence of the UVB rays.
No matter the color of the skin, the freckles are conditioned by irregular distribution of the melanin pigment in the skin. Freckles are essentially larger deposits of melanin in one spot of the skin.
How important is genetics for the development of the freckles?
Skin type in a person, and also genetics, are very important factors which influence the appearance of freckles. Freckles are genetically conditioned especially in persons with lighter skin, blond or red hair. Many researches have determined that there is an equal number of freckles in identical twins, which doesn’t happen in fraternal twins.
In a rare genetically determined disease – xeroderma pigmentosum, the appearance of freckles is absolutely genetically conditioned. The appearance of freckles in redheaded persons with this disease is common.
In another genetically determined disease – neurofibromatosis, the appearance of freckles under the armpits is very common.
What is the medical significance of freckles?
Skin freckles have no health risks. Also, they don’t have a tendency to become malignant. In rare cases when freckles are joined with aforementioned diseases (xeroderma pigmentosum or neurofibromatosis), tracking and testing of the basic disease are necessary.
In some cases freckles and spots on the skin demand concern:
Lentigo maligna – This is an unusual surface slow-spreading skin cancer which develops on the face of elderly persons who have a history of long-term Sun exposure. During several years, if not treated properly and on time, this lentigo can become a more aggressive malignant carcinoma – lentigo maligna melanoma.
American academy of dermatology recommends an examination of pigmented changes and spots once a year. It is very important to visit a dermatologist in case of an appearance of new moles, their growth or change in color and also bleeding. Skin cancer can be treated if it is diagnosed and removed in its early phases.
More about possible ways for freckles and spots removal read here.
Spec. Dr. Svetlana Djurisic, dermatologist
Dermatological clinic DERMATIM, Belgrade, Serbia