What Causes Moles? Cautery, Shave and Surgical Removal Explained, and Which Moles Should Never Be Lasered Off

A mole (melanocytic nevus) is a brown to black bump or spot formed when pigment cells cluster together in the skin. Most people have anywhere from a few to several dozen moles, and almost all of them are normal and harmless. The most common questions are "which method is best for removing a mole: cautery, cutting or laser?" and "which moles should I watch?" In this article, a dermatologist explains what causes moles, how each removal method differs, which moles should be removed or worried about, and why some moles must never be burned or lasered off without being sent for testing.

What causes moles?

Moles form when pigment-producing cells (melanocytes) gather in clusters instead of spreading evenly. Related factors include genetics, cumulative sun exposure, and hormonal changes, such as puberty and pregnancy, which can darken moles or bring new ones. By the depth of the pigment cells, moles are divided into superficial moles that are usually flat, compound moles that are slightly raised, and deep moles that form pale domes. The small dots Thai people call "fly droppings" are a type of small mole.

Which moles should be removed?

There are two main reasons to remove a mole: for appearance or annoyance, and for diagnosis when it might be abnormal. Situations in which removal may be considered include

• Moles that are rubbed regularly, such as under a bra strap or waistband, or nicked often by a razor, causing irritation or bleeding.

• Moles that affect your confidence on the face or another clearly visible spot.

• Moles with suspicious features under the ABCDE rule. These must be removed for testing, not for cosmetic reasons.

How do mole cautery, shave excision and surgical excision differ?

Many people confuse the methods. They suit different moles, and they differ in scarring and in whether a sample is sent for testing.

• Electrocautery or laser (mole cautery) suits small raised moles that are confirmed not to be cancer. It is quick and leaves a small wound, but the key limitation is that no tissue is available for testing, because the mole is destroyed. It is used only for moles the doctor is confident are normal.

• Shave excision removes a raised mole level with the skin and allows the tissue to be sent for testing. It suits some raised moles.

• Excision with stitches removes the whole mole down to the deeper layer and closes the wound with sutures. It provides the complete tissue sample for pathology testing and suits suspicious moles or flat dark moles that need certainty. Although the wound becomes a stitched line, it gives the clearest diagnosis.

So the choice of method depends less on speed or price and more on the mole's features and the need for testing.

Why must some moles not be burned or lasered off?

This is the principle that separates treatment by a specialist dermatologist from mole burning at a general shop. A pigmented mole that is not yet known to be non-cancerous should not be burned or lasered off, because

• Cautery or laser destroys the mole so no tissue remains for testing. If it were actually melanoma, an important early diagnosis and treatment would be missed.

• Incomplete destruction may cause an abnormal mole to behave worse.

• A mole that is not fully removed often grows back and looks distorted, making it harder to assess in the future.

For this reason, the doctor will always examine the mole and use a dermoscope first. If there is any suspicion, the mole is removed and sent for testing; if the doctor is confident it is normal, cautery or laser may be considered for cosmetic reasons.

Warning signs: which moles need prompt medical attention

Use the ABCDE rule: A for asymmetry, B for irregular or notched borders, C for uneven color with several shades, D for diameter larger than 6 mm, and E for evolving or rapid change, along with these additional signs

• A mole that grows quickly, itches, bleeds, or forms a sore that does not heal

• A mole that looks clearly different from your other moles (the "ugly duckling")

• A mole on the palms, soles, under a nail, or on a mucous membrane, locations where skin cancer needs particular attention in Asian people

• A mole that appears new after age 40

Aftercare and recurrence

• The procedure is done under local anesthetic, so it is not painful while it is being done. Afterward, keep the wound clean and dry as instructed.

• Asian skin can develop post-procedure dark marks (PIH). Strict sun protection helps reduce them.

• A mole that is not removed down to the root can come back, especially after shallow cautery. Removing the whole mole has a lower chance of recurrence.

• Scarring depends on the method and location. The doctor will choose the method that balances appearance and safety.

Frequently asked questions (FAQ)

What causes moles?

Moles form when pigment cells cluster together in the skin, linked to genetics, sun exposure and hormones. Most are normal, harmless and not contagious.

How is mole cautery different from mole excision?

Cautery suits raised moles confirmed not to be cancer. It is quick and leaves a small wound, but no tissue is available for testing. Excision removes the whole mole and closes it with stitches, and the tissue is sent for pathology testing. It suits suspicious moles or flat dark moles.

Which moles are dangerous and need prompt medical attention?

A mole that is asymmetrical, has uneven borders, uneven color, is larger than 6 mm, changes quickly, bleeds or itches, as well as a mole on the sole, under a nail, or one that appears new after age 40, should be seen by a doctor to rule out cancer.

Can a mole simply be lasered off?

A pigmented mole should not be lasered or burned off before a doctor has assessed that it is not cancer, because no tissue will remain for testing. Once it is confirmed normal, laser may be used for cosmetic reasons. If there is any suspicion, it must be removed and tested first.

Will mole cautery leave a scar or grow back?

When done by a doctor with a suitable method, the chance of scarring is low, but Asian skin may develop temporary dark marks. Shallow cautery that does not remove the mole to the root is more likely to recur than removing the whole mole.

Can I remove a mole myself with creams or acid?

No. Mole creams or acids burn the skin and cause wounds and dark marks, the depth cannot be controlled, and they destroy the mole tissue so it cannot be tested for cancer. Have a dermatologist assess it and remove it with a suitable method.

Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed 3 August 2026