Symptoms and localization

Actinic keratoses usually manifest as rough, scaly, often itchy or painful lesions on the skin that can vary in color from flesh-colored to reddish brown. They may also be characterized by hardening or thickening of the skin. Lesions can vary in size and shape, from small patches to larger plaques that can reach several centimeters in diameter. Most actinic keratoses occur in areas most exposed to the sun, particularly the face, scalp, hands, forearms, and neck. Actinic keratosis is usually diagnosed by a clinical examination of the skin by a dermatologist. The lesions are usually easy to identify and may also be examined by biopsy to confirm the diagnosis.

Therapy

Treatment of actinic keratosis depends on the severity of the lesions and the risk that they will develop into squamous cell carcinoma. Common treatment methods include topical application of drugs such as 5-fluorouracil, imiquimod, or diclofenac, cryotherapy (cold therapy), laser therapy, photodynamic therapy, and surgical excision.

Topical treatment with 5-fluorouracil or imiquimod can help effectively remove actinic keratoses by killing the abnormal cells and stimulating normal skin regeneration. Diclofenac can also be applied topically and inhibits the enzyme cyclooxygenase-2, which is involved in the development of skin cancer.

Cryotherapy is used to remove actinic keratoses through targeted exposure to cold. Another method is laser therapy, which uses a laser beam to remove the lesions. Photodynamic therapy is another effective method for treating actinic keratoses. It involves applying a light-sensitive substance to the lesions and then irradiating them with light to destroy the abnormal cells. In some cases, surgical removal of the lesion may be necessary, especially if there is a risk that the actinic keratosis has developed into an invasive squamous cell carcinoma. Surgical removal is also an effective method for removing lesions that are large or difficult to access.

Course and prognosis

If actinic keratoses are not treated, there is an increased risk that they will develop into invasive squamous cell carcinoma. However, with early treatment, prognosis is usually good. Some studies show that the incidence of squamous cell carcinoma in patients with actinic keratoses can be reduced with early treatment.

Incidence and risk factors: Actinic keratoses are common skin lesions, especially in middle-aged and older people. The risk of developing actinic keratoses depends on several factors, including the number of sunburns and cumulative sun exposure over a lifetime, skin type, and family history of skin cancer.

Prevention

The best way to prevent actinic keratoses is to take sun protection measures, such as wearing protective clothing, avoiding direct sun exposure during the hot part of the day, and applying sunscreen with a high SPF. It is also recommended to perform regular skin examinations and treat suspicious lesions early.

Pathogenesis

The exact pathogenesis of actinic keratosis is not fully understood, but it is thought to be caused by chronic sun exposure and ultraviolet radiation, which lead to DNA damage in the skin. This damage can then lead to abnormal cell proliferation and differentiation, resulting in the characteristic skin lesions.

Definition

Actinic keratoses are flat, rough, scaly lesions on the skin caused by UV radiation. They can occur in a variety of sizes and shapes and are often reddish in color. Actinic keratoses are considered premalignant lesions because they increase the risk of developing a malignant skin lesion, such as squamous cell carcinoma.

Classification

Actinic keratoses are usually classified according to their clinical appearance. The most common types are:

Actinic keratosis of the scalp

Actinic keratosis of the face and limbs

Actinic keratosis of the back of the hand

Staging

There is no official staging for actinic keratosis. However, in some cases, severe lesions may be considered precancerous and treated as such.

Similar diseases

Squamous cell carcinoma: A malignant skin tumor that develops from the cells of the upper layer of the skin (epithelial cells). Squamous cell carcinoma can develop from actinic keratoses.

Basal cell carcinoma: A malignant skin tumor that develops from the cells of the lower layer of the skin (basal cells). Basal cell carcinomas can also develop from actinic keratoses.

Literature

Werner RN, Stockfleth E, Connolly SM, et al. Evidence- and consensus-based (S3) Guidelines for the Treatment of Actinic Keratosis – International League of Dermatological Societies in cooperation with the European Dermatology Forum – Short version. J Eur Acad Dermatol Venereol. 2015 Nov;29(11):2069-79. doi: 10.1111/jdv.13180. epub 2015 Oct 12. PMID: 26388224.

Schmitt JV, Miot HA. Actinic keratosis: a clinical and epidemiological revision. An Bras Dermatol. 2012 Jul-Aug;87(4):425-34. doi: 10.1590/s0365-05962012000400002. PMID: 22892798; PMCID: PMC3699933.

Web links

Actinic keratosis on the website of the German Dermatological Society: https://www.derma.de/aktinische-keratose/

Actinic keratosis on the website of the National Center for Tumor Diseases (NCT): https://www.nct-heidelberg.de/de/patienten-angehoerige/erkrankungen/aktinische-keratose.html