Actinic keratosis (AK) is a common skin condition that is often referred to as “sunspots” or “sun damage” which is associated with chronic sun exposure. AKs typically appear as rough, scaly skin patches. AKs are most commonly seen in fair-skinned individuals and who reside in low latitude regions. While AK itself is not cancerous, they are regarded as precancerous. Left untreated, AK can lead to a skin cancer called squamous cell carcinoma (SCC).
The primary cause for actinic keratosis (AK) is exposure to long-term and cumulative ultraviolet (UV) radiation from the sun and indoor tanning. Chronic exposure to UV radiation can damage the DNA in skin cells and lead to mutations that promotes cell proliferation and inhibits cell death. Keratinocytes are the cells that make up the outermost layer of the skin, and they are responsible for producing a tough, protective protein called keratin. In response to chronic sun exposure, keratinocytes undergo changes that accelerate the development of AKs. These changes may include alterations in the expression of genes that regulate cell growth and differentiation, as well as the accumulation of DNA damage and mutation can trigger the activation of oncogenes or the inactivation of tumor suppressor genes. The abnormal growth of keratinocytes in AKs can lead to the formation of scaly, rough, or crusty patches of skin.
Some AKs can be pigmented due to the presence of melanin in the skin. Melanin is the pigment that gives color to the skin, hair, and eyes, and it is produced by cells called melanocytes. In certain cases, melanocytes become more active in response to sun exposure, leading to an increase in melanin production and the development of pigmented lesions, such as freckles, solar lentigines, and pigmented AKs. Pigmented AKs are more difficult to diagnose and may be mistakenly distinguished for other types of pigmented skin lesions, such as melanoma.
Diagnosis of actinic keratosis is closely related to the duration and intensity of ultraviolet radiation exposure. In addition to exposure to natural sunlight, indoor tanning also accounts for cellular destruction of skin cells. Indoor tanning devices emit both UVA and UVB radiation, which can penetrate deep into the skin and cause damage to the DNA in skin cells.
Moreover, ionizing radiation is a type of high-energy radiation that has enough energy to attack cell components and destroy DNA of cells. Persons with outdoor occupations such as airline pilots are shown to have an elevated risk for AK or cancerous progression leading to SCC.
Not to mention, individuals with weaker immune systems after undergoing organ transplantation, taking immunosuppressive drugs or experiencing HIV infection are at higher risk of AK due to ineffective growth and repair of damaged cell.
The diagnosis of actinic keratosis (AK) is usually made based on the clinical appearance of the lesion. AKs typically present as rough, scaly, or crusty patches of skin that may be pink, red, or brown in color. The primary lesion is a rough, erythematous papule with white to yellow scale. Patients may report tenderness. Another option could be biopsy which can confirm the diagnosis or rule out other skin conditions, such as squamous cell carcinoma.
Co2 laser is a mainstay of medical treatment for actinic keratosis. The treatment involves the use of laser to vaporize and destroy abnormal cells in the lesion. Another considerable option is photodynamic therapy (PDT). It uses a photosensitizing agent and a light source to destroy abnormal cells in the body. The light activates the photosensitizing agent, causing it to produce a form of oxygen that destroys the abnormal cells. Both treatments are relatively non-invasive. It is generally safe and well-tolerated, yet some patients may experience pain, redness, or swelling after the procedure.
The incidence of AK has been increasing over the past several decades, which may be due in part to increased sun exposure and the popularity of tanning in the past. It is important to note that AKs are a preventable condition, and taking steps to protect the skin from UV radiation can reduce the risk of developing these lesions. This includes using sunscreen, wearing protective clothing, seeking shade during peak sun hours, and avoiding indoor tanning. Regular skin checks and early detection of AKs can also help prevent the progression of these lesions to skin cancer.