Moles that change color or increase in number: Cause for concern?

1) Dear Alice,

Over the span of the last couple of years, I have noticed a significant number of moles appearing on my body. They have been appearing everywhere from my neck to my inner thighs. I had one on my neck since childhood, but now have so many more. Is this normal? Is it something I should be concerned with? And does child bearing have any relevance to this happening?

2) Dear Alice,

I have a mole which has turned very dark purple, and grown a bit in size (still small). This is the second time it has done this — last time was a couple of weeks ago, and it slowly faded back to almost nothing until today. Should I be very concerned about this?

Dear Readers,

The sudden change in appearance of a mole (a dermatologist may call it a nevus or nevi, if there are multiple) or a recent uptick in their quantity can certainly provoke some questions. Luckily, most types of moles are harmless. However, while some change in the appearance and number of moles may occur over time, the time to seek medical attention is if and when the moles in question exhibit signs of concern (more on this later).

The majority of moles and other unclassifiable blemishes are considered benign, or non-cancerous. However, certain characteristics of each may denote a higher risk for melanoma, which is a type of skin cancer. Moles that you’re born with are known as congenital moles. These moles don’t typically impart a risk for skin cancer, unless the one you’re born with is quite large (more than eight inches in diameter). Another type of mole is an acquired mole, which appear after a person is born. Adults tend to have anywhere from 10 to 40 of these moles on their bodies. Generally, these moles are considered to be low risk. But if a person has more than 50 acquired moles, then it may be a good idea to check in with a health care provider, as this could be put you at a higher risk for melanoma. And Reader 1, you’re right about pregnancy potentially increasing the number of moles on the body. Additionally, they may multiply during puberty as well, as hormonal changes may increase the number of moles on the body.

While some types of moles are harmless, others may be less so. Atypical moles are ones that also appear after a person is born, but are larger in size, may not be round, and be may be more than one color. While these moles often have these characteristics, they’re typically not cancerous. Similarly, some folks develop what are called spitz nevus, which are moles that are often pink (but can also have shades of red, black, brown), dome-shaped, and may bleed. These are difficult to distinguish from moles that may be cancerous — but often they’re benign as well.

Spots or moles that warrant a second look by a medical professional include any that appear to have changed in color or size, start to bleed, or start to become itchy. They may also become painful over time. To determine whether any of the moles you’ve described warrant further attention, it’s a good idea to follow the "ABCDEs", which are five characteristics of moles to watch out for:

  • Asymmetry: If one half of the mole(s) is unlike the other half in shape or color.
  • Border: If the mole has an irregular, blurred, or poorly defined border on its edges.
  • Color: If the mole varies in color from one area to another, or has shades of tan, brown, and black, or even white, red, or blue. Most moles are brown and uniformly a darker shade then your natural skin tone.
  • Diameter: If the diameter is greater than a quarter of an inch or about six millimeters. The larger the mole (especially if it's growing fast), the greater the cause for concern.
  • Evolving: If a mole or skin lesion looks different from the others on your body, or is changing in size, shape, height, or color (especially if it turns entirely black).


Checking on your moles regularly is the best way to make sure they’re less likely to cause a problem later. If there’s a change that you’ve recently observed in any of your moles — such as the one you’ve observed, Reader 2 — it's recommended that you make an appointment with your health care provider or a dermatologist (a health care provider that focuses on hair, skin, and nails). It’s been noted that cancerous moles may exhibit a range of these characteristics — as some may have just a few of them, while others may exhibit them all. So, when in doubt, get it checked out! In addition to keeping a close eye on your moles, exposure to the sun can also affect the intensity of freckles and the appearance of moles. The proper use of sunscreen and other sun-protection methods are helpful prevention tools to reduce your chances of getting skin cancer. For more information about new moles and moles in general, the American Academy of Dermatology is a great resource to check out.

Hope this helps you both “mole” over the information about these skin changes!

Last updated Jan 22, 2021
Originally published Jul 03, 2009

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