Solar keratosis: Epidemiology, pathogenesis, presentation and treatment

Abstract

Solar keratosis is a common problem encountered by dermatologists, particularly in Australia. Solar keratosis is most commonly found on sun-exposed areas such as the scalp, face and forearms. UV radiation is thought to be the major aetiological factor, with age, immunosuppression and human papillomavirus being important contributing factors. Solar keratosis usually presents as a discrete, variably erythematous and irregular lesion with a scaly surface. Although the exact rate of malignant transformation to squamous cell carcinoma is unknown, the majority of squamous cell carcinomas appear to arise from within solar keratosis. For this reason, solar keratosis is commonly treated and, consequently, an increasing number of therapeutic options is now available. Traditional therapies, such as liquid nitrogen cryotherapy, are still popular, but newer choices, such as photodynamic therapy and imiquimod cream, are now providing further options with similar efficacy and superior adverse effect profiles, albeit at a higher cost.

Consensus recommendations on the use of daylight photodynamic therapy with methyl aminolevulinate cream for actinic keratoses in Australia

“…Although c‐PDT is a successful treatment for AK,5, 9, 24 the unpredictability of tolerance during treatment in some patients, extended treatment times, and costly instrumentation has limited its use. Daylight PDT is a simple and practical new treatment option for AK that allows large areas of actinic damage to be treated with reduced in‐clinic treatment times and little or no pain.…”

“…Using the Olsen three‐point scale,3 AK lesions are categorised as grade I (single or few lesions, better felt than seen), grade II (moderately thick lesions, easily felt and seen), or grade III (hyperkeratotic lesions). Significantly, AK have the potential to progress to invasive squamous cell carcinomas (SCC), however the actual risk of malignant transformation is poorly defined, with the reported risk varying from <0.025 to 16% per year 4, 5, 6. Because of the malignant potential and the unpredictability of the transformation from AK to SCC, consensus guidelines recommend that AK are removed using appropriate therapies to prevent progression to invasive disease 5, 7, 8…”

“…Conventional photodynamic therapy (c‐PDT) utilising photosensitising agents such as 5‐aminolaevulinic acid or methyl aminolevulinate (MAL) has emerged as a successful treatment for AK, particularly for the treatment of large areas of field change 5, 7, 9. During treatment, the topically applied agents are converted to photoactive porphyrins (e.g., protoporphyrin IX [PpIX]), through enzymes in the haem biosynthetic pathway10 and afterwards activated by dedicated light‐emitting equipment (e.g.…”

Ingenol Mebutate 0.06% Gel for Field Treatment of Actinic Keratosis on 250 cm2 of Skin on Trunk and Extremities: A Randomized Dose-Finding Trial

“…embarrassment about scarring), and can negatively impact health-related quality of life. [34][35][36][37] In this study, ≥ 70% of patients reported improved cosmetic outcomes with IngMeb, with improved appearance and feel of the treated area.…”

Skin Cancer Prevention: Recent Evidence from Randomized Controlled Trials

“…Beyond these are further billions-around $1.2 billion in the United States [9•]-expended treating the related and highly prevalent skin lesions, actinic keratoses (AKs). AKs affect 5 % to 25 % of people in the United Kingdom and United States and up to 60 % in Australia [10,11], and are one of the strongest risk factors for skin cancer.…”