Skin cancer most often develops on areas of the body that get more exposure to the sun’s ultraviolet (UV) rays. The skin disease usually strikes the face, chest, arms, and hands, but it can also show up on the scalp, ears, lips, and neck. It can also appear on other parts of the body that never see light, including beneath your fingernails, on the bottom of your feet, and on your genitals. While skin cancers most often appear as a suspicious mole, freckle, or spot, the particulars depend on the type of skin cancer:

Actinic Keratosis

Actinic keratosis appears as a scaly or crusty lesion, most often on the scalp, face, ears, lips, back of hands and forearms, shoulders, or neck—those areas most frequently exposed to the sun. They are sometimes so small that they are found by touch and not by sight. They may feel like a small patch of sandpaper on your skin.

Basal Cell Carcinoma

Basal cell carcinoma often appears as a waxy bump, usually in the areas of the body most often exposed to the sun’s ultraviolet radiation.

Squamous Cell Carcinoma

Squamous cell carcinomas most commonly occur on the more sun-exposed body parts, but can also appear on the inside of your mouth or on your genitals. The tumors caused by squamous cell carcinoma can take a variety of forms, including:

  • a firm, red nodule
  • a flat lesion with a scaly crust
  • an ulcer in the mouth
  • a red, raised patch on the anus or genitals

Squamous cell carcinoma is also known to cause intense itching, which only further irritates and inflames the skin. Scratching the skin can lead to infections that need to be treated with antibiotics.

Melanoma

Melanoma, the deadliest form of skin cancer, most often develops on the lower legs in women and on the chest, back, head, and neck in men. Here are some characteristics that may indicate that a mole, freckle, or spot is a sign of melanoma:

Asymmetrical/Irregular Borders

If the edges of a mole or freckle are irregular rather than fairly even all around, it could signal a cancerous change.

Change in Color

Color variation within a mole or freckle can be another telltale sign. Keep an eye out for these changes in color or appearance:

  • different shades of tan, brown, or black or in some cases, red, white, or blue
  • a large brown spot with dark speckles inside

Although less common, other potentially cancerous lesions are dark lesions found on the palms, soles of feet, fingertips, or toes, or on the mucous membranes of the mouth, nose, genitals, or anus.

Diameter

In some cases, having a mole or freckle that’s larger than six millimeters, which is about the diameter of a pencil eraser, can be a sign of skin cancer.

Lack of Healing

If you have a mole, freckle, or growth that doesn’t heal or bleeds, have your doctor check it out right away.

Signs of Less Common Skin Cancers

Although uncommon, it is helpful to recognize the symptoms of these rarer sking cancers:

  • Kaposi sarcoma develops in the blood vessels of the skin and appears as reddish-purple patches on parts of skin that are heavily sun-exposed.
  • Merkel cell carcinoma leads to the growth of firm, shiny nodules on sun-exposed skin and in hair follicles.
  • Sebaceous gland carcinoma is an aggressive cancer that results in hard, painless nodules, most often appearing on the eyelid.