Actinic Cheilitis (AC)

Cheilitis is a state of inflamed lips that happens due to three factors—infection of the lip and skin conditions, nutritional deficiency, or allergy, toxin, medication, and injury.

The lip surface consists of hairy skin, vermilion border, oral mucosa, and vermilion. The vermilion part of the inferior or lower lip becomes dry, cracked, diffused, and inflamed when the lip surface is frequently or excessively exposed to sunlight. This pre-cancerous or malignant condition is categorized as actinic cheilitis (AC). It is generally known as sailors-lip, solar cheilitis, or farmer’s lip.

Patients of AC have common symptoms of dry and chapped lips. They are prone to actinic keratosis, a scaly or brittle growth of skin caused by ultraviolet (UV) exposure. The actinic keratosis is also known as solar keratosis. Almost 6–10% of patients with AC can also develop squamous cell carcinoma (SCC) of lips; SSC is a skin cancer that occurs on all parts of the body due to extreme sun exposure.

General Risk Factors

1. People with white skin are at more risk of developing actinic cheilitis.
2. Chronic exposure of UV rays is one of the major risk factors of this disease.
3. Smokers have a strong association with this disease, who live in hot or subtropical areas, particularly outdoor workers.
4. Poor oral health and ill-fitted dentures can also add to this problem.

It generally arises in men and the elderly and is three times more common in males than in females, as men are more exposed to the sun and they use little or no cosmetics to protect themselves.

Case Study

Prolonged exposure of UV radiation also makes the skin more elastic and freckling, which lead to AC. In the history of tobacco users, Caucasians were frequently identified with the disease.

A study was conducted in 2004 among tobacco users who were outdoor workers (age: 50 years and above) involved in construction works, fishing or farming. Among them, a group of 65 people were diagnosed with actinic cheilitis, and the ratio between male and female was 12:1.

46.1% of cases are reported with lesions on their lip’s right side since they prefer holding cigarettes on that side. 72.3 % were found between at a stage between moderate dysplasia and aggressive SCC, and the remaining 27.7 % of patients had a mild form of epithelial dysplasia.

Characteristics of Actinic Cheilitis

Depending upon its appearances, actinic cheilitis has varied characteristics, which are classified into: unique appearances, perioral and intraoral appearances, and extra-oral appearances.

• Unique appearances: The lower lip with a non-curative ulcerated area along with scaling or white patches is the unique characteristic of AC. A bulbous swelling appears on the lower lip without vermilion border, and becomes dry when it progresses to actinic cheilitis.
• Perioral/intraoral appearances: Lesions are found on tissues of perioral region of the lip and may extend to a wet line area in advanced cases. The appearance is elevated, keratotic and crusty, with ulcerated lesions. Sometimes the structure of AC on the lower lip looks like a combination of red as well as white lesions. There may or may not be ulceration.
• Extra-oral appearances: A small fine line (vermilion border) in the lower lip is visible when it is in normal condition; however, when it is exposed to the sun frequently, the tissue gets destroyed . These fine lines disappear and form white patches, and become rough and scaly.

Complications of Actinic Cheilitis

Secondary conditions, symptoms, and some other factors complicate AC. In most circumstances, the difference between symptoms and complications remains unclear or random.

It predisposes the skin to intraepidermal carcinoma (Bowen disease or squamous cell carcinoma in situ) and invasive squamous cell carcinoma. O ther factors such as wart virus (oncogenic human papillomavirus), alcohol abuse, and immunosuppression can increase the complexity .

The reason for the progression of AC to SCC is cell proliferation regulatory proteins and cancer suppressor genes. If the lip has visible tender or enlarged nodule development or persistent ulcers, then it could be suspected to be invasive SCC.  

The surface of epithelial cell has parakeratin. When it continuously gets exposed to solar rays, this thick layer in the regions of the spinous cell becomes irregular and results in the elongation of rete ridges, epithelial extensions into the underlying tissue. Some areas of the rete ridges consist of a bulbous structure and show dysplastic changes in the epithelium. This condition is called solar elastosis (damage of collagen in the connective tissues), which is a frequent and important sign of AC. It is a pre-stage of AC.

Leukoplakia is one of the most common forms of AC and it may lead to SCC of the oral mucosa, which is defined as an uncontrolled growth of abnormal cells (white patch) arising in the squamous cells i.e., in the epidermis.