Moles form because cells in the skin called melanocytes grow in clusters instead of being spread out evenly. These melanocytes produce pigment, which gives skin its color, and when they group together, they create a mole that appears as a small colored spot or bump on the skin. The exact causes of why these clusters form are not fully understood but are believed to involve a combination of genetic factors and exposure to ultraviolet (UV) light from the sun or tanning beds. Moles often appear during childhood and adolescence and can also emerge at times of hormonal changes, such as during pregnancy or puberty. Key factors contributing to mole formation include:
- Genetic predisposition, as moles often run in families.
- Sun exposure, particularly UV radiation, which can stimulate melanocytes to cluster.
- Hormonal changes that can cause new moles to develop or existing moles to change.
- Some moles are present at birth (congenital), but most appear later in life.
Most moles are benign (noncancerous), but new or changing moles in adults should be monitored as they can sometimes become cancerous (melanoma). Regular skin examinations are recommended to track changes in moles.
