Focus on moles Focus on moles

They usually look like small dark dots, and can be found on your skin, scalp, eyes, and even nails. If there are warning signs, it is best to talk to a specialist.

Advisor: María Soledad Aluma
Dermatologist specialized in Dermatological Surgery and Mohs Micrographic Surgery

Moles are benign lesions composed of cells called melanocytes, which are responsible for producing pigment. They are medically known as nevus, and are classified as congenital or acquired. Congenital nevi originated from birth, and acquired nevi appear due to external factors such as ultraviolet radiation. Dermatologist María Soledad Aluma, specialist in Dermatological Surgery and Mohs Micrographic Surgery, explains that “the exact causes that lead to moles are complex, multifactorial, and not yet fully understood.” As they are generally benign, they do not represent an imminent health risk, but according to Aluma, it is necessary to be aware of them and check their size, color, and irregular edges, since they can have dimensions of less than one centimeter up to more than 20. “People who have giant congenital nevi are at a greater risk of developing melanoma,” states the specialist. Also, it has been shown that the use of sunscreen from childhood reduces their appearance and evolution. It is important to consult with a specialist if you notice a type of abnormality with your moles to rule out any suspicion of melanoma and to prevent it.

ABCDE of Melanoma

Recommended method for analyzing five criteria and detecting abnormalities:

  • Asymmetry: one half does not coincide with the other.
  • Borders: shape is uneven or irregular.
  • Color: it is not uniform.
  • Diameter: size is bigger than a pencil eraser.
  • Evolution: it grows with time and changes shape and color

3rd type of most common and severe skin cancer is melanoma, states specialist Aluma.

When is there a risk?

If a mole has irregularities in its characteristics, there is a greater risk of melanoma, and it is necessary to talk to a doctor. The genetic factor must be taken into account, as family history may play a role. Even in number, as generally a person can have between 10 to 40 moles. If you have more than 50, it is also a sign you need to have them checked.

30 % to 40 % of all melanomas appear from a mole.

One in every 100 people is born with a giant congenital mole.


Although nevi do not tend to appear more or less frequently according to gender, it is known that they can increase and darken in women during pregnancy. Their numbers grow in childhood and early adulthood and then gradually regress. After the age of 40, it is not common for them to appear; and they are less numerous in dark-skinned people due to the protective effect of melanin.