Telling Brown Spots Apart — Moles, Age Spots, and Lentigines
Many people notice a new brown mark on their face, hand, or shoulder and wonder whether it's a simple mole, an age spot that comes with getting older, or a lentigo. Although these can all look similar in shade of brown at a glance, they differ in how they form, their cellular characteristics, and why they may warrant closer attention.
What exactly is a mole?
A mole, medically known as a melanocytic nevus, is a benign lesion that forms when melanocytes (pigment-producing cells) cluster and multiply in a specific area of skin. Color can range from brown to nearly black, and moles may be present from birth (congenital) or develop later in life (acquired). They typically have a round, well-defined border and tend to grow gradually before stabilizing. That said, if a mole changes shape, size, or color asymmetrically, or its border becomes irregular, it should be evaluated by a dermatologist without delay.
Are age spots related to aging?
Age spots, medically called seborrheic keratoses, are benign growths that form when epidermal cells proliferate excessively due to cumulative aging and sun exposure. They often appear slightly raised with a rough, scaly texture, and their color can range from light brown to dark brown or black. They commonly appear on the face, forehead, and trunk after the 40s, and their number tends to increase with age, though this varies from person to person. Most age spots are benign, but if one suddenly grows larger, bleeds, or becomes itchy, it's worth getting a differential evaluation.
How is a lentigo different from a mole or age spot?
A lentigo is a flat brown patch that forms not from an increase in the number of melanocytes, but from excess melanin pigment accumulating in the basal layer of the epidermis. Unlike a mole, it doesn't sit raised above the skin and instead lies nearly flush with the surface. Lentigines tend to appear in sun-exposed areas such as the face, backs of the hands, and arms. Solar lentigines (sometimes called age spots or liver spots) result from long-term cumulative UV exposure, and consistent sun protection may help reduce their occurrence.
What if it's hard to tell these apart by eye?
These three types of lesions can look quite similar in color and location, making them difficult to distinguish with the naked eye. It's especially important not to confuse an ordinary mole with melanoma, a type of skin cancer. Dermatologists often reference five warning signs — asymmetry, border irregularity, color variation, diameter over 6mm, and evolving size or shape — as a general guide. However, these are only reference points; an accurate diagnosis requires a dermatologist's visual exam and, when needed, dermoscopy or a biopsy.
When might removal be considered?
Some people seek removal for cosmetic reasons, but if a lesion has been changing or needs a differential diagnosis, an accurate assessment should come first. Once a brown lesion is confirmed benign, options such as age spot and lentigo removal may be considered, though the specific method and number of sessions vary depending on the lesion's type, size, location, and individual skin condition. Because recurrence or new lesions can occur even after treatment, periodic skin checks can be helpful.
Most brown spots are benign, but rather than deciding on your own to leave a changing or concerning mark alone, it's safer to have it checked by a specialist. This information is intended for general reference only; an accurate diagnosis and treatment require consultation with a board-certified dermatologist.