Actinic keratoses Flashcards
Define actinic keratoses.
Actinic keratosis (AK) lesions are skin-coloured, yellowish, or erythematous, ill-defined, irregularly shaped, small, scaly macules or plaques localised in sun-exposed areas of the body.
They can potentially progress into squamous cell carcinoma (SCC).
What is the aetiology of actinic keratoses?
Chronic exposure to UV rays, mostly UVB (290 to 320 nanometres) is a key aetiological factor resulting in damage to keratinocyte DNA and has been implicated in skin carcinogenesis.
What are risk factors for actinic keratoses?
Chronic exposure to UVB radiation (290-320nm)
Light-coloured skin, freckling, and albinism
Age >40 years
Male sex
Immunocompromise
Xeroderma pigmentosum
Summarise the epidemiology of actinic keratoses.
The proportion of adults with at least one AK lesion is lower (11% to 26%) in temperate northern hemisphere countries (e.g., the US and England), and higher (40% to 60%) in countries closer to the equator (e.g., Australia).
What are signs and symptoms of actinic keratoses?
Single or multiple scaly macules or plaques
Scaly lesions with a hyperkeratotic surface
Well-defined, scaly, brown lesions
Lesions resembling seborrhoeic keratosis, melanocytic naevus, and early malignant melanoma
Hypertrophic conical-shaped protuberances growing from the surface of the skin
Scaly red roughness with induration, fissuring, and ulceration of the lower lip to the commissures
Lesion on sun-exposed area of body
What investigations should be performed for actinic keratoses?
CLINICAL DIAGNOSIS
Dermoscopy
Skin biopsy
What is the management for actinic kekratoses?
Cryosurgery
Chemical peels
Topical therapy - Fluorouracil 0.5%
What are complications associated with actinic keratoses?
Photodynamic therapy-related induction or aggravation of light-induced diseases
Salicylism related to salicylic acid and Jessner’s peels
Cryosurgery-related hypopigmentation
Contact sensitisation related to diclofenac
Severe transient irritation related to imiquimod and fluorouracil
Progression to Bowen’s disease
Progression to invasive SCC
What is the prognosis of actinic keratoses?
The risk of progression of AKs to invasive squamous cell carcinoma (SCC) has been calculated to be between 0.025% and 16% per year.
The calculated lifetime risk of malignant transformation for a patient with AKs followed up for 10 years is between 6.1% and 10.2%.
Although spontaneous regression has been reported to be as high as 25.9% of AKs over a 12-month period, 15% of them have reappeared later.
