Skin cancer is the most common form of cancer, developing when skin cells grow out of control, most often due to DNA damage from ultraviolet (UV) radiation. While many people routinely check sun-exposed areas like their arms and legs, the scalp is a frequently overlooked but highly vulnerable site for this malignancy. Approximately 13% of all skin cancers occur on the scalp. Understanding the visual appearances of these growths is important, especially since the scalp is exposed to high levels of direct sunlight.
Why Skin Cancer on the Scalp is Hard to Detect
The unique anatomy of the scalp presents several challenges that often delay the discovery of skin cancer. Hair provides a natural barrier, which prevents suspicious spots from being easily seen, both by the individual and by a partner. This coverage can effectively obscure a lesion, allowing it to grow deeper before it is noticed. The difficulty of self-examination compounds this issue, as the scalp is an awkward area to inspect without multiple mirrors or assistance. For those with thinning hair or baldness, the scalp receives chronic, intense UV exposure, significantly raising the risk of cancerous development.
How Non-Melanoma Cancers Manifest on the Head
Non-melanoma skin cancers, primarily Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC), are the most common types found on the scalp.
Basal Cell Carcinoma (BCC)
Basal Cell Carcinoma typically appears as a pearly or waxy bump that may be flesh-colored, pink, or translucent. These lesions are often shiny and may be mistaken for a mole, a persistent pimple, or a small, non-healing injury. A common feature of BCC is a rolled, slightly raised border with a central indentation, sometimes revealing tiny, irregular blood vessels on the surface. Larger BCCs may have crusted, oozing areas and are characterized by bleeding easily, even from minor trauma. The most telling sign of this growth is a sore that fails to completely heal or one that appears to heal only to return later. BCCs generally grow slowly but can cause significant local damage by invading surrounding tissue if left untreated.
Squamous Cell Carcinoma (SCC)
Squamous Cell Carcinoma, the second most common type, often presents as a persistent, rough, scaly patch. These patches are typically red and may feel tender, sometimes resembling dry skin, eczema, or psoriasis. The appearance can progress to a firm, raised nodule or a warty growth that may crust and bleed. A precursor lesion, known as Actinic Keratosis, is frequently observed on the sun-damaged skin of the scalp and appears as a rough, sandpaper-like spot. SCC can manifest as an open sore that refuses to close completely or a crater-like lesion that expands rapidly. SCCs on the scalp are of particular concern because they have a higher potential to spread beyond the skin compared to BCC.
Recognizing the Signs of Scalp Melanoma
Melanoma is a less common but more aggressive form of skin cancer that can begin as a new spot or a change in an existing mole on the scalp. Recognizing the distinct features described by the ABCDE criteria is important.
- Asymmetry: One half of the spot does not match the other half.
- Border irregularity: The edges are ragged, notched, blurred, or poorly defined.
- Color variation: The spot contains multiple shades of black, brown, or tan, and sometimes includes areas of white, red, or blue.
- Diameter: Most melanomas are larger than 6 millimeters, roughly the size of a pencil eraser, when diagnosed.
- Evolving: The mole or spot is changing in size, shape, color, or height.
Melanoma on the scalp can sometimes be non-pigmented, known as amelanotic melanoma, which appears as a pink, red, or flesh-colored bump. The appearance of a spot that looks different from all others on the skin—the “ugly duckling” sign—should also raise suspicion.
Next Steps After Finding a Suspicious Spot
If you notice any new, changing, or unusual spot on your scalp, schedule an appointment with a dermatologist or primary care physician. Describe exactly what you have observed, including any changes over time, bleeding, or lack of healing. A healthcare provider will perform a thorough skin examination, often utilizing a handheld magnification device called a dermatoscope to inspect the lesion closely. If the spot is visually suspicious, the physician will recommend a skin biopsy. This procedure involves taking a small sample of the growth for laboratory testing. A biopsy is the only way to confirm a diagnosis of skin cancer and determine the specific type.