Actinic keratosis

Not to be confused with Seborrheic keratosis.

Actinic keratosis
Other namesSolar keratosis, senile keratosis (SK)
Actinic keratosis on the back of a hand
SpecialtyDermatology

Actinic keratosis (AK), sometimes called solar keratosis or senile keratosis,[1][2] is a pre-cancerous[3] area of thick, scaly, or crusty skin.[4][5] Actinic keratosis is a disorder (-osis) of epidermal keratinocytes that is induced by ultraviolet (UV) light exposure (actin-).[6]

These growths are more common in fair-skinned people and those who are frequently in the sun.[7] They are believed to form when skin gets damaged by UV radiation from the sun or indoor tanning beds, usually over the course of decades. Given their pre-cancerous nature, if left untreated, they may turn into a type of skin cancer called squamous cell carcinoma.[5] Untreated lesions have up to a 20% risk of progression to squamous cell carcinoma,[8] so treatment by a dermatologist is recommended.

Actinic keratoses characteristically appear as thick, scaly, or crusty areas that often feel dry or rough. Size commonly ranges between 2 and 6 millimeters, but they can grow to be several centimeters in diameter. Actinic keratoses are often felt before they are seen, and the texture is sometimes compared to sandpaper.[9] They may be dark, light, tan, pink, red, a combination of all these, or have the same color as the surrounding skin.

Given the causal relationship between sun exposure and actinic keratosis growth, they often appear on a background of sun-damaged skin and in areas that are commonly sun-exposed, such as the face, ears, neck, scalp, chest, backs of hands, forearms, or lips. Because sun exposure is rarely limited to a small area, most people who have an actinic keratosis have more than one.[10]

If clinical examination findings are not typical of actinic keratosis and the possibility of in situ or invasive squamous cell carcinoma (SCC) cannot be excluded based on clinical examination alone, a biopsy or excision can be considered for definitive diagnosis by histologic examination of the lesional tissue.[11] Multiple treatment options for actinic keratosis are available. Photodynamic therapy (PDT) is one option for the treatment of numerous actinic keratosis lesions in a region of the skin, termed field cancerization.[12] It involves the application of a photosensitizer to the skin followed by illumination with a strong light source. Topical creams, such as 5-fluorouracil or imiquimod, may require daily application to affected skin areas over a typical time course of weeks.[13]

Cryotherapy is frequently used for few and well-defined lesions,[14] but undesired skin lightening, or hypopigmentation, may occur at the treatment site.[15] By following up with a dermatologist, actinic keratoses can be treated before they progress to skin cancer. If cancer does develop from an actinic keratosis lesion, it can be caught early with close monitoring, at a time when treatment is likely to have a high cure rate.

  1. ^ Rapini RP, Bolognia J, Jorizzo JL (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. pp. Chapter 108. ISBN 978-1-4160-2999-1.
  2. ^ Logan CM, Rice MK (1987). Logan's Medical and Scientific Abbreviations. J. B. Lippincott and Company. p. 512. ISBN 0-397-54589-4.
  3. ^ Prajapati V, Barankin B (May 2008). "Dermacase. Actinic keratosis". Canadian Family Physician. 54 (5): 691, 699. PMC 2377206. PMID 18474700.
  4. ^ Freedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. ISBN 0-07-138076-0.
  5. ^ a b Quaedvlieg PJ, Tirsi E, Thissen MR, Krekels GA (2006). "Actinic keratosis: how to differentiate the good from the bad ones?". European Journal of Dermatology. 16 (4): 335–9. PMID 16935787.
  6. ^ Cite error: The named reference :15 was invoked but never defined (see the help page).
  7. ^ "actinic keratosis" at Dorland's Medical Dictionary
  8. ^ Weedon D (2010). Weedon's Skin Pathology (3rd ed.). Elsevier. ISBN 978-0-7020-3485-5.
  9. ^ Moy RL (January 2000). "Clinical presentation of actinic keratoses and squamous cell carcinoma". Journal of the American Academy of Dermatology. 42 (1 Pt 2): 8–10. doi:10.1067/mjd.2000.103343. PMID 10607350.
  10. ^ Stockfleth E, Kerl H (November–December 2006). "Guidelines for the management of actinic keratoses". European Journal of Dermatology. 16 (6): 599–606. PMID 17229598.
  11. ^ "Actinic keratosis - Symptoms, diagnosis and treatment | BMJ Best Practice". bestpractice.bmj.com. Retrieved 25 November 2019.
  12. ^ Werner RN, Stockfleth E, Connolly SM, Correia O, Erdmann R, Foley P, et al. (November 2015). "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". Journal of the European Academy of Dermatology and Venereology. 29 (11): 2069–79. doi:10.1111/jdv.13180. PMID 26370093. S2CID 19644716.
  13. ^ Szeimies RM, Torezan L, Niwa A, Valente N, Unger P, Kohl E, et al. (July 2012). "Clinical, histopathological and immunohistochemical assessment of human skin field cancerization before and after photodynamic therapy". The British Journal of Dermatology. 167 (1): 150–9. doi:10.1111/j.1365-2133.2012.10887.x. PMID 22329784. S2CID 10970924.
  14. ^ Ibrahim SF, Brown MD (July 2009). "Actinic keratoses: a comprehensive update". The Journal of Clinical and Aesthetic Dermatology. 2 (7): 43–8. PMC 2924136. PMID 20729970.
  15. ^ Thai KE, Fergin P, Freeman M, Vinciullo C, Francis D, Spelman L, et al. (September 2004). "A prospective study of the use of cryosurgery for the treatment of actinic keratoses". International Journal of Dermatology. 43 (9): 687–92. doi:10.1111/j.1365-4632.2004.02056.x. PMID 15357755. S2CID 24067576.
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