A skin tag, medically known as an acrochordon, is a small, common growth of skin tissue. These growths are classified as benign tumors, meaning they are non-cancerous. They appear as soft, flesh-colored, or slightly darker flaps of skin that affect almost half of the adult population at some point in their lives.
The Structural Components of a Skin Tag
A skin tag is fundamentally an outward projection of normal skin layers, but in a highly concentrated and localized form. Histologically, the growth consists of two main parts: a central core and an outer covering. The characteristic soft, fleshy nature of the skin tag comes from its internal structure, which is a fibrovascular core.
This core is composed of loosely arranged collagen fibers, the protein that provides structure to the skin’s middle layer. Interspersed within this collagen matrix are small blood vessels and occasional nerve cells, giving the tag its nutrient supply and sensitivity.
The entire core is enveloped by an outer layer of epidermal cells, the same stratified squamous epithelium that covers the rest of the body. This outer layer is often slightly thickened or overgrown. The distinctive appearance of the skin tag, often described as a balloon on a string, is due to this epithelial layer wrapping around the central core.
The growth typically attaches to the underlying skin by a narrow stalk, called a peduncle, which is why they appear to dangle. This structure differentiates skin tags from other skin lesions like warts, which tend to be flat and have a rougher, more solid texture. Skin tags usually measure between one to five millimeters in diameter, though they can occasionally grow larger.
Where and Why Skin Tags Develop
The primary mechanical factor driving the formation of skin tags is constant friction. These growths tend to form in areas where skin rubs against adjacent skin or where clothing and jewelry rub against the skin surface. This continuous mechanical irritation is thought to stimulate the cells in the skin to overgrow and proliferate.
Common anatomical sites for development include the neck, the armpits, the groin folds, and under the breasts. They can also frequently occur on the eyelids, where blinking and fine wrinkles create minor friction. These locations are all characterized by skin creases where movement causes repeated rubbing.
Several systemic conditions and physiological changes are known to increase the likelihood of developing skin tags. Obesity is a significant risk factor, as increased body mass leads to more skin folds and greater skin-on-skin friction. This mechanical stress contributes to their frequency in heavier individuals.
Metabolic factors, particularly insulin resistance, also show a strong association with skin tags. High levels of insulin and insulin-like growth factor (IGF-1) circulating in the bloodstream can stimulate the growth of skin cells, leading to the formation of these lesions. Hormonal shifts, such as those that occur during pregnancy, often trigger the appearance of new skin tags.
When to Consult a Doctor
Although skin tags are benign, it is important to monitor any skin growth for unusual changes that might indicate a different type of lesion. A medical professional should examine any growth that changes rapidly in size, color, or texture. While skin tags may darken slightly over time, the appearance of multiple colors, particularly black, white, or red, warrants prompt evaluation.
Spontaneous bleeding or non-healing sores on the growth are significant indicators that the lesion may not be a simple skin tag. Typical skin tags do not bleed unless they are traumatized, such as by being caught on clothing or jewelry. Pain, persistent itching, or a change in texture from soft and pliable to firm or hard also require a professional diagnosis.
In rare instances, a more serious skin cancer, such as a basal cell carcinoma, can sometimes mimic the appearance of a skin tag, especially in its early stages. Consulting a dermatologist for a definitive diagnosis ensures that the growth is correctly identified. Medical removal is also recommended if the tag is causing irritation, pain, or if removal is desired for cosmetic reasons.