Actinic keratosis, Causes, Signs and Symptoms, Diagnosis and Treatment.

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Chapters

0:00 Introduction
1:25 Causes of Actinic keratosis
2:32 Symptoms of Actinic keratosis
2:55 Diagnosis of Actinic keratosis
3:18 Treatment of Actinic keratosis






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. Notably, AKs 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 AK 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 AK have more than one.[10]

If clinical examination findings are not typical of AK 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 AK are available. Photodynamic therapy (PDT) is one option the treatment of numerous AK 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, AKs can be treated before they progress to skin cancer. If cancer does develop from an AK lesion, it can be caught early with close monitoring, at a time when treatment is likely to have a high cure rate.