All about Actinic keratosis
Actinic keratosis is an area of the skin damaged by ultraviolet radiation that appears in zones exposed to the sun for years. Its appearance is variable.
Why does actinic keratosis develop?
Actinic keratosis is caused by chronic exposure of the skin to ultraviolet (UV) radiation from the sun or other sources that emit UV radiation (such as tanning booths or sunbeds). UV radiation causes alterations in the DNA of skin cells. When DNA repair mechanisms are depleted or fail, these alterations lead to the onset of mutations in skin cells called keratinocytes, which in turn leads to the development of actinic keratosis.
Actinic keratosis risk factors
Sun light is the main cause of actinic keratosis. This means that we can all develop the condition. However, there are certain predisposing factors that cause UV light exposure to accumulate. You are at higher risk of developing actinic keratosis if:
- You are an elderly person: The longer you have been exposed to the sun, the higher the risk you have of developing actinic keratosis.
- Your head is not well covered by hair: As there is little hair on the head, the protection against radiation decreases. Males have a higher risk to develop AK.
- You work outdoors.
- You play sports or other recreational activities outdoors often (golf, tennis…).
- You live in a country close to the equator: the latitude and altitude of the place of residence influence the amount of UV radiation received.
- You expose yourself to artificial sources of UV radiation, such as tanning beds/booths.
- You have fair skin, or sensitive skin, freckles; have red or blond hair, and blue or lightcolored eyes: all these features predispose you to be more sensitive to UV radiation.
There are other less common factors that can also increase the risk of actinic keratosis:
- Having a weak or weakened immune system, whether due to illness or treatment with immunosuppressants (which lower the body's defenses), for instance, as a result of having received an organ transplant.
- Having a syndrome involving alterations in DNA repair mechanisms, such as albinism.
- Suffering from photosensitivity. Certain drugs―for example diuretics―can make your skin more sensitive to sunlight.
- Being exposed to toxic substances, such as arsenic, or drugs that alter normal cell functioning.
References
- 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 [Internet]. J Eur Acad Dermatol Venereol. 2015;29(11):2069-79. Available at: http://doi.wiley.com/10.1111/jdv.13180
- Gohara M, Morison W, Sarnoff DS. Clothing: Our first line of defence [cited 2020 Feb 6]. In: The Skin Cancer Foundation [Internet]. New York (USA): The Skin Cancer Foundation; c2019. - [approx. 5 screens]. ]. Available at: https://www.skincancer.org/skin-cancer-prevention/sun-protection/
- BAD: British Association of Dermatologists. Actinic Keratoses - Also Known as Solar Keratoses [Internet]. London (United Kingdom): BAD; 2007 May [revised 2019 Nov; cited 2020 Feb 19]. 5 p. Available at: http://www.bad.org.uk/shared/get-file.ashx?id=66&itemtype=document
Frequently asked questions about actinic keratosis
Actinic keratosis is not hereditary, although some of the factors that favor its appearance, such as fair skin or freckles, are so. Actinic keratosis is not contagious.
Actinic keratosis is an uncontrolled proliferation of keratinocytes: the most abundant cells of the epidermis (the outermost layer of the skin), that become abnormal4. Some actinic keratoses can turn into a type of skin cancer called epidermoid carcinoma or invasive squamous cell carcinoma1,4. Although rare, this type of cancer can spread to other tissues, and it is therefore recommended to treat all actinic keratoses.
Furthermore, a person with actinic keratosis is at higher risk of developing any type of skin cancer compared to another person of the same age who does not. People who have a higher number of actinic keratoses also run a higher risk of skin cancer.
Some actinic keratoses resolve spontaneously, especially if sunscreen or protection is used, although most remain as they are. Others may progress into invasive squamous cell carcinoma. Unfortunately, it is impossible to know in advance which ones will in fact progress into invasive squamous cell carcinoma. The clinical course of the condition cannot be predicted.
Actinic keratosis lesions can heal and disappear spontaneously or through treatment. However, it is very common for old lesions to recur or for new ones to come out. The presence of a single actinic keratosis is already a sign that chronic damage from solar radiation has occurred, and hence there is a risk that other lesions could appear. Therefore, if you have actinic keratosis, your doctor will monitor you regularly, and will recommend that you seek consultation if you notice new lesions or any changes in the ones you already have.
Protecting yourself from the sun is essential to prevent the appearance of actinic keratosis and slow down progression. Following the following measures strictly is key to keeping actinic keratoses under control:
Use sunscreen and clothing that covers your body.
- Avoid peak sun hours.
- Avoid artificial sunlight (sun beds/tanning salons).
- Check your skin at home and schedule an appointment with the dermatologist on a regular basis.