Small Dark Spots ("Fly Droppings"): What Causes Them, How a Dermatologist Tells Them Apart From Moles, Freckles and Skin Cancer, and How to Remove Them Without Dark Marks
"Fly droppings" (khi malaeng wan in Thai) is the everyday name for small dark brown to black dots or bumps on the skin. Medically they are usually small moles (melanocytic nevus), formed when pigment cells gather in clusters. Most are harmless, but they need to be examined properly, because dark spots on the skin belong to the same group of lesions that can hide melanoma, a type of skin cancer. In this article, a dermatologist explains what causes these spots and moles, the types that exist, how doctors tell them apart from skin cancer, including dermoscopy and the ABCDE rule, and the key reason pigmented spots should not be burned or lasered off before cancer has been ruled out.
What causes small dark spots and moles?
Moles and small dark spots form when pigment cells (melanocytes), instead of spreading evenly, gather in clusters within the skin, which appear as dark dots or bumps. Related factors include:
Genetics. The number of moles is partly inherited. People whose parents have many moles tend to have many too.
Sun exposure. Accumulated UV exposure, especially sunburn in childhood, is linked to having more moles and is a risk factor for melanoma.
Hormones. Puberty and pregnancy can make existing moles darker or bring new spots.
A mole may be present from birth (congenital nevus) or develop gradually later in life (acquired nevus). Large congenital moles carry a different level of risk and should be monitored by a doctor.
There are several types of moles and small dark spots
Medically, moles are classified by where the pigment cells sit within the layers of the skin, which explains why some spots are flat and others are raised.
Junctional nevus. The pigment cells sit at the junction between the epidermis and the dermis. It looks flat, dark brown to black, and is the type that best matches what Thai people call "fly droppings".
Compound nevus. The cells lie in both the upper and deeper layers. It looks slightly raised and pigmented.
Intradermal nevus. The cells lie in the dermis. It looks dome-shaped and light-colored or skin-colored, and is often seen on the face in adults.
Other special moles such as halo nevus (a mole surrounded by a white ring) and blue nevus (a deep blue-black mole caused by pigment in the deeper layers), which doctors need to distinguish from skin cancer.
How do doctors tell small dark spots from skin cancer?
Most dark spots on the skin are harmless, but melanoma is a skin cancer that must be identified early because it is highly treatable when found early. The tools dermatologists use are the ABCDE rule together with dermoscopy.
The ABCDE rule for self-checking
A – Asymmetry. The shape is uneven; one half does not match the other.
B – Border. The edge is notched, irregular or blurred.
C – Color. The color is uneven, with several shades in one spot.
D – Diameter. It is larger than 6 millimeters, or keeps growing.
E – Evolving. It changes quickly in size, color or shape, or itches or bleeds.
There is also the "ugly duckling" sign: a mole that looks clearly different from your other moles should be examined.
The role of dermoscopy and areas that need extra care
Doctors use a dermatoscope to look at pigment structures beneath the skin surface. A normal mole usually shows a regular network pattern, while melanoma often shows abnormal patterns, blue-white areas, or irregularly scattered lines of color. Areas that doctors watch with particular care include:
Palms and soles. Moles here need a careful look at the skin ridge pattern, because the type of melanoma that is common in Asian people often appears on the soles.
Under the nails. A brown-black band under a nail that becomes wider, darker, or spreads color to the skin around the nail (Hutchinson's sign) needs prompt examination.
Mucous membranes, such as inside the mouth or the genital area.
Warning signs: when to see a doctor
A spot that grows quickly, changes color or changes shape within a short time
Uneven color, irregular border or asymmetry according to the ABCDE rule
Bleeding, ulceration, itching or rapid thickening for no clear reason
A mole on the palms, soles, under the nails or on mucous membranes
A mole that is clearly different from the others, or a new mole appearing after age 40
How to remove small dark spots and moles safely
The most important principle when removing a pigmented spot is to confirm first that it is not cancer, and only then choose a method, rather than removing it right away for cosmetic reasons.
Always have it assessed and examined with a dermatoscope first. If it clearly fits a normal mole, removal for cosmetic reasons can then be considered.
For a spot that is suspicious or uncertain, it should be removed and sent for pathology (excisional biopsy), because this is the only way to confirm that it is not melanoma.
Do not use electrocautery or laser on a pigmented spot before it is certain that it is not cancer. Destroying the lesion leaves no tissue to diagnose, and if it is in fact melanoma, important treatment would be missed. This is the difference between treatment by a specialist doctor and burning off spots at an ordinary shop.
Once it is confirmed not to be cancer, a flat dark spot may be treated with a Q-switched or Picosecond laser, while a raised mole is treated with electrocautery or removed by excision, depending on its appearance and location.
A key point for Asian skin is that every procedure carries a chance of post-procedure dark marks (PIH), so sun protection and aftercare as instructed by the doctor are essential. You also should not burn off or "eat away" these spots yourself with herbs or corrosive liquids sold at markets, because this risks burns, permanent scars and a missed skin cancer diagnosis.
Frequently asked questions (FAQ)
What causes small dark spots ("fly droppings")?
They are small moles formed when pigment cells gather in clusters in the skin. They are related to genetics, accumulated sun exposure and hormones. They are not caused by infection and are not contagious.
Are they dangerous? Could they be cancer?
Most are harmless, but pigmented spots belong to the same group of lesions that can be melanoma. If a spot fits the ABCDE rule, grows quickly, has uneven color or an irregular border, or is on the sole or under a nail, see a doctor to rule out cancer.
How do these spots differ from moles and freckles?
A small dark spot is a small, flat mole formed from pigment cells. An ordinary mole is the same thing but usually larger or more raised. A freckle is a flat, light-colored spot related to sun exposure and does not come from clusters of pigment cells in the same way.
Can I just burn or laser a small dark spot right away?
You should not burn or laser a pigmented spot before a doctor has assessed that it is not cancer, because destroying the lesion means it can no longer be examined under the microscope. If there is any suspicion, the doctor will remove it and send it for pathology first, and then choose a suitable method once it is confirmed safe.
Will removal leave a scar or dark mark?
When it is done by a doctor with a method suited to the type and location, the chance of scarring is low, but Asian skin may develop temporary dark marks. Sun protection and aftercare as advised after the procedure are needed.
Can I remove them myself?
No. Burning or corroding a spot yourself risks burns, infection and scarring, and above all a missed skin cancer diagnosis. Always have a dermatologist assess it first.
Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed August 3, 2026
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