Skin tags, known medically as acrochordons, are extremely common, harmless growths that appear on the skin’s surface. Understanding the distinct characteristics of these benign lesions versus the warning signs of malignancy can provide peace of mind. While a true skin tag is non-cancerous, confusion often arises because some early skin cancers can mimic the look of an innocent growth.
What Exactly Is a Skin Tag
A skin tag (acrochordon) is a small, soft, benign growth that appears to hang off the skin. These lesions are composed of a core of loose collagen fibers and blood vessels, all encased in a layer of epidermis. They are typically flesh-colored or slightly hyperpigmented.
The size of a skin tag is generally small, often ranging from two to five millimeters, though some can grow larger. A defining feature is their pedunculated nature, meaning they are often attached to the skin by a thin, fleshy stalk or peduncle. Skin tags commonly form in areas where skin rubs against skin or clothing, such as the neck, armpits, groin folds, and under the breasts.
The Myth of Skin Tag Transformation
It is a misconception that a pre-existing skin tag can transform into a malignant tumor. True acrochordons are benign growths that do not carry a known risk of becoming cancerous. They are structurally different from the cells that form skin cancers.
The source of this persistent worry often lies in misidentification, as certain types of skin cancer can occasionally resemble a benign skin tag. A growth that is initially mistaken for a skin tag but is later diagnosed as cancerous was never a true acrochordon to begin with. For example, some basal cell carcinomas can present as raised, irregular nodules that might be confused with a tag.
Key Differences Between Benign Skin Tags and Malignant Growths
A harmless skin tag is typically soft, smooth, and uniform in color, matching the surrounding skin or appearing light brown. They are stable, meaning their size and shape usually remain consistent over long periods.
In contrast, malignant growths often display characteristics that can be memorized using the “ABCDE” mnemonic. Asymmetry means one half of the growth does not match the other, whereas a skin tag is generally symmetrical. Border irregularity describes edges that are notched, blurred, or ragged, unlike the smooth borders of a typical tag. Color variation within the lesion, featuring shades of red, white, blue, black, or multiple tones of brown, is highly suggestive of malignancy. A diameter greater than six millimeters is the Diameter criterion. The most telling sign is Evolving, which refers to any change in the growth’s size, shape, color, or elevation over weeks or months.
Other signs should prompt concern, as they rarely occur with an uncomplicated skin tag. These include spontaneous bleeding without trauma, a persistent open sore or ulceration that does not heal, or the development of a crusted surface. A growth that becomes painful, persistently itchy, or unusually firm to the touch also warrants professional evaluation.
Next Steps: When to Seek Professional Evaluation
When any new or changing skin growth appears, consult a healthcare professional, preferably a dermatologist. If you observe any of the suspicious characteristics, such as rapid growth, color change, or bleeding, a prompt evaluation is necessary.
During the appointment, the dermatologist will first conduct a thorough visual inspection. They may use a specialized handheld device called a dermatoscope, which uses magnification and polarized light to visualize structures beneath the skin’s surface, improving diagnostic accuracy.
If the growth remains suspicious after dermoscopy, the definitive diagnostic procedure is a skin biopsy. This involves removing a small tissue sample for microscopic examination. The biopsy provides a conclusive identification of the cells, confirming whether the lesion is a harmless skin tag or a malignant tumor.