Actinic cheilitis

by Jason Wasserman MD PhD FRCPC
November 21, 2024

Actinic cheilitis is a condition that affects the lips, especially the lower lip, due to long-term exposure to ultraviolet (UV) rays from the sun. It causes the skin of the lips to become rough, scaly, or discolored. Actinic cheilitis is considered a precancerous condition, meaning that if left untreated, it has the potential to develop into a type of skin cancer called squamous cell carcinoma. Early diagnosis and treatment can prevent progression to cancer.

Is actinic cheilitis a type of skin cancer?

No, actinic cheilitis is not skin cancer, but it is a precancerous condition. This means it shows changes in the skin that increase the risk of developing squamous cell carcinoma. While most cases of actinic cheilitis do not progress to cancer, it is important to monitor the condition and treat it early to reduce the risk.

What does actinic cheilitis look like?

Actinic cheilitis typically appears as dry, rough patches on the lips. These patches may be scaly, cracked, or discolored, and the lips may look pale or blotchy. The affected area might feel tender, and in some cases, small sores or ulcers can develop. The lower lip is more commonly affected because it receives more direct sun exposure than the upper lip.

What causes actinic cheilitis?

The leading cause of actinic cheilitis is chronic exposure to ultraviolet (UV) radiation from the sun or artificial sources like tanning beds. People with lighter skin tones are more susceptible because they have less natural protection against UV rays. Other risk factors include outdoor occupations, older age, and a history of excessive sun exposure.

How is this diagnosis made?

Actinic cheilitis is diagnosed through a physical examination of the lips and, if necessary, a biopsy. During a biopsy, a small piece of tissue is removed from the affected area and examined under a microscope by a pathologist. This helps confirm the diagnosis and rule out squamous cell carcinoma or other conditions.

Microscopic features

Under the microscope, actinic cheilitis shows changes in the outer layer of the skin, called the epithelium, and the underlying connective tissue.

• Epithelial changes: The epithelium becomes disorganized and may be thicker than usual in some areas (hyperplasia) or thinner in others (atrophy). The cells in the epithelium show atypia, which means they appear abnormal in size, shape, or structure. These changes are a sign of precancerous activity.
• Keratin production: The epithelium often shows excessive keratin, a protein that helps protect the skin. This keratin can form a thick, scaly layer on the lip surface.
• Connective tissue changes: The connective tissue beneath the epithelium often shows solar elastosis, a condition caused by sun damage. This is seen as a build-up of abnormal elastic fibers, giving the tissue a disorganized appearance.

These microscopic changes help distinguish actinic cheilitis from other conditions and guide treatment decisions.

Margins

Margins refer to the edges of the tissue removed during a biopsy or excision to diagnose or treat actinic cheilitis. Both types of procedures—biopsies and excisions—include margins, and examining these margins is an important part of determining whether all the abnormal tissue has been removed.

• Margins in biopsy material: Only a small portion of the affected area is removed when a biopsy is performed. The margins of this sample help pathologists understand whether the abnormal changes extend beyond the sampled area. If abnormal cells are present at the edges of the biopsy, it may suggest that more tissue needs to be evaluated or removed.
• Margins in excisions: When the entire lesion is removed (an excision), the margins are checked to ensure all abnormal tissue has been completely excised.
  • Clear (negative) margins mean no abnormal cells are found at the edges, indicating the actinic cheilitis has likely been entirely removed.
  • Positive margins mean abnormal cells are present at the edges, suggesting some precancerous tissue remains. In this case, additional treatment may be needed.