Epidemiology

Summary features (1):

• Prevalence rates highest in countries that have high sun exposure and have largely fair-skinned population.
• Highest prevalence rate has been documented in Australia – over 40% in individuals aged over 40 years.
• Countries with low levels of sun exposure such as the UK and Ireland, have lower rates of 19-25%, in individuals aged over 60 years.
• Increased prevalence with age.
• The trunk and forehead are most commonly affected. (2)
• There is an increased risk of actinic keratoses, and most non-melanoma skin malignancies, in patients receiving immunosuppressive treatment.

Note that about 20-70% of solar keratoses regress spontaneously over 1-2 years, but typically 15% recur (3).

References

1. Barthelmann S, Butsch F, Lang BM, et al. Seborrheic keratosis. J Dtsch Dermatol Ges. 2023 Mar;21(3):265-77.
2. Seaton E, Madan V. Benign keratinocytic acanthomas and proliferations. In: Barker J, Griffiths C, Bleiker T, eds. Rook's textbook of dermatology. 10th ed. Hoboken, NJ: John Wiley & Sons, Ltd; 2024.
3. Jackson JM, Alexis A, Berman B, et al. Current understanding of seborrheic keratosis: prevalence, etiology, clinical presentation, diagnosis, and management. J Drugs Dermatol. 2015 Oct;14(10):1119-25.