A mole, or nevus, is a common skin growth that develops from a cluster of melanocytes, which are the specialized cells responsible for producing the skin pigment melanin. Most adults have between 10 and 40 of these growths, which are typically uniform in color and shape. While the presence of a bleeding mole can cause significant anxiety, the event is not always an indication of malignancy. Understanding the context and cause of the bleeding is the first step in determining the level of concern and deciding when a professional medical evaluation is necessary.
Immediate Assessment: Why Moles Bleed
The most frequent reason a mole bleeds is minor trauma, which is considered a benign cause. Moles that are raised or located in areas of high friction are particularly susceptible to injury. This external damage can result from scratching, nicking it while shaving, or constant rubbing against clothing or jewelry. In these cases, the bleeding is usually minor, stops quickly with light pressure, and the mole shows no other concerning changes.
Bleeding that occurs spontaneously or is persistent is a far more serious sign that warrants immediate attention. Malignant moles, such as melanoma, grow rapidly and aggressively, invading surrounding tissue. This unchecked growth leads to the formation of fragile, thin-walled blood vessels within the lesion. These abnormal vessels break easily, causing the mole to bleed without external provocation. As the cancer progresses, the surface may break down (ulceration), creating an open sore that may ooze or bleed continuously, often accompanied by other changes in appearance.
Recognizing the Signs of Concern
Any mole that begins to bleed, even after mild trauma, should be evaluated for other characteristics that suggest a potential for malignancy. These warning signs are categorized by dermatologists to help identify lesions that require further testing. The initial sign is Asymmetry, meaning one half does not mirror the other half in size, shape, or color.
The second characteristic involves the Borders of the mole, which may appear poorly defined, blurred, notched, or scalloped. In contrast, a benign mole typically has borders that are smooth and distinct from the surrounding skin. The third feature is Color variation, including shades of tan, brown, and black, or areas of white, red, or blue pigment within the same lesion.
The fourth factor is Diameter, as melanomas are frequently larger than 6 millimeters (the size of a pencil eraser) when first diagnosed. The most important characteristic is Evolution (change over time), which includes any noticeable modification in size, shape, or color. Spontaneous bleeding, ulceration, crusting, or persistent itching are strong indicators that the mole requires professional assessment.
Seeking Professional Evaluation and Diagnosis
Any mole exhibiting spontaneous bleeding, ulceration, or any of the structural changes described should prompt a consultation with a dermatologist. This professional assessment should occur even if the bleeding has stopped, as the underlying cause may still be present. Early detection of melanoma is paramount, as the five-year relative survival rate for localized disease is nearly 99%.
The diagnostic process begins with a thorough visual inspection, often enhanced by a specialized handheld device called a dermatoscope. Dermoscopy is a non-invasive technique that uses magnification and a polarized light source to examine structures beneath the skin’s surface that are invisible to the naked eye. This allows the physician to better evaluate patterns of pigment and blood vessels to distinguish between benign and malignant lesions.
If the visual and dermoscopic examination suggests malignancy, a biopsy is necessary to obtain a definitive diagnosis. An excisional biopsy, which removes the entire mole and a small margin of surrounding tissue, is the preferred method for any lesion highly suspicious for melanoma. The tissue is then sent to a laboratory for microscopic analysis to confirm the presence of cancer cells.