Why does the Sun affect freckles?

Summer often means sunshine, beaches, and... freckles. These small marks on the skin, often called "sun kisses," are as fascinating as they are puzzling. Why do they appear mostly in summer? What is their role? Let's dive into the mystery of freckles.


Freckles are actually the skin's response to the Sun's ultraviolet (UV) rays. According to board-certified dermatologist Jill S. Waibel, they are a form of protective mechanism against these harmful rays. Sun exposure triggers the skin to produce melanin, a pigment responsible for skin color and which manifests as tanning.

Melanin has the property of dispersing UV rays, thus preventing them from penetrating the skin and damaging the DNA. However, some areas of the skin produce more melanin than others. These melanin-rich areas are what we call freckles.

Freckles are more visible in the summer and tend to fade or disappear during months when UV radiation is weaker. But not all freckles react the same way to seasonal Sun exposure, notes board-certified dermatologist Rebecca Kazin.

There are two main types of freckles: ephelides and solar lentigines, also known as age spots. Ephelides are the most common and are generally small and light brown. They appear on areas of the skin frequently exposed to the Sun, such as the face, arms, and shoulders. Solar lentigines, on the other hand, are associated with cumulative Sun damage and do not fade.

Solar lentigines are generally larger and darker than ephelides and are more common in older individuals. They appear when UV rays damage the skin's DNA, altering the behavior of melanin-producing cells.

If you are concerned about a spot or notice rapid changes, it is advised to consult a healthcare professional.