Skin cancer is the most common form of cancer, and the scalp receives significant sun exposure, making it a frequent site for lesions. Understanding the appearance of these growths is important because skin cancers on the head can sometimes behave more aggressively or be detected at a later stage than those found elsewhere on the body. The scalp’s unique anatomy, including a high concentration of blood vessels, means cancers here may have a greater potential for local growth or spread if not identified early. Due to the presence of hair, lesions are often hidden, delaying diagnosis until the cancer is more advanced.
Visual Characteristics of Non-Melanoma Skin Cancers
The two most common forms of skin cancer, Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC), are collectively known as non-melanoma skin cancers.
BCC frequently appears on the scalp as a shiny, translucent bump that may be pink, red, or clear. This type of lesion often has a waxy or pearly quality, sometimes featuring tiny, irregular blood vessels near the surface, known as telangiectasias. A common presentation of BCC is a sore that bleeds easily after minor trauma, such as brushing hair, and then seems to heal only to return later, never fully resolving.
The morpheaform subtype of BCC is less common but particularly deceptive, as it can resemble a white or yellowish scar-like patch with poorly defined borders. These lesions are often flat or slightly depressed.
SCC typically presents as a firm, reddish nodule or a rough, scaly patch with a crusted surface. These growths may resemble a persistent wart or a patch of skin irritation that feels rough to the touch. Actinic keratosis, a common precancerous lesion that can develop into SCC, appears as a rough, sandpaper-like patch on sun-damaged areas of the scalp. SCC lesions may also manifest as an open sore with raised edges that will not close and may bleed or crust over repeatedly.
Identifying Malignant Melanoma on the Scalp
Melanoma, the least common but most serious form of skin cancer, often presents as a new or changing mole. Its appearance is typically assessed using the ABCDE rule.
ABCDE Rule
- Asymmetry: One half of the lesion does not match the other.
- Border irregularity: The edges are jagged, notched, or blurred.
- Color variation: The lesion displays multiple shades of brown, black, red, white, or blue.
- Diameter: Melanomas are usually larger than 6 millimeters, or about the size of a pencil eraser.
- Evolving: Refers to any change in the lesion’s size, shape, color, texture, or the onset of new symptoms like bleeding or itching.
The Evolving characteristic is particularly relevant for the scalp, as melanomas in this area tend to be nodular, meaning they grow deeper into the tissue more quickly.
A significant challenge is amelanotic melanoma, which lacks the dark melanin pigment and therefore does not adhere to typical color criteria. These lesions may appear as a pink, red, or flesh-colored growth, sometimes resembling a benign scar or a non-melanoma skin cancer. In these cases, recognizing the ‘Evolving’ sign becomes the most important indicator for seeking prompt evaluation.
Unique Challenges of Scalp Self-Examination
Detecting skin cancer on the scalp is inherently difficult because the presence of hair acts as a physical barrier to visibility. Patients frequently mistake early lesions for benign, common occurrences such as an insect bite, a scratch from a comb, or simple dandruff and psoriasis patches. This misinterpretation contributes to the tendency for later diagnosis of scalp lesions.
To perform an effective self-examination, use a full-length mirror and a handheld mirror, ideally in a brightly lit room. A simple comb or a blow-dryer set on a cool setting can be used to systematically part the hair in small sections, allowing the underlying skin to be clearly seen. Work methodically from the front hairline to the nape of the neck, paying close attention to the crown, which receives the highest solar exposure. Because the back and crown remain difficult to visualize, asking a trusted partner or family member to conduct regular checks of these areas can greatly improve the chance of early detection.
Next Steps After Finding a Suspicious Spot
If a spot on the scalp exhibits any of the visual characteristics mentioned, or if it is new, changing, or simply unusual, the next step is to schedule an appointment with a dermatologist. A specialist uses a dermatoscope, a magnifying tool that illuminates and examines the deeper layers of the skin, which aids in distinguishing benign from suspicious growths. If the lesion is concerning, a biopsy will be performed to obtain a tissue sample for laboratory analysis and a definitive diagnosis.
The specific type of biopsy depends on the suspected cancer and the size of the lesion. A shave biopsy removes a superficial layer of the skin and is often used for growths suspected to be BCC or SCC. For lesions requiring a deeper sample, such as those suspected to be melanoma, a punch biopsy removes a small, circular core of tissue that extends into the deeper layers of the skin. If melanoma is strongly suspected, an excisional biopsy, which removes the entire lesion along with a margin of surrounding healthy skin, is often preferred to ensure proper staging and pathology.