More than 80% of countries in the world lack information on the epidemiology of psoriasis.[4]Parisi R, Iskandar IYK, Kontopantelis E, et al. National, regional, and worldwide epidemiology of psoriasis: systematic analysis and modelling study. BMJ. 2020 May 28;369:m1590.
https://www.bmj.com/content/369/bmj.m1590.long
http://www.ncbi.nlm.nih.gov/pubmed/32467098?tool=bestpractice.com
Published data report prevalence ranging from 0.09% to 11.43%.[5]Gibbs S. Skin disease and socioeconomic conditions in rural Africa: Tanzania. Int J Dermatol. 1996 Sep;35(9):633-9.
http://www.ncbi.nlm.nih.gov/pubmed/8876289?tool=bestpractice.com
[6]Danielsen K, Olsen AO, Wilsgaard T, et al. Is the prevalence of psoriasis increasing? A 30-year follow-up of a population-based cohort. Br J Dermatol. 2013 Jun;168(6):1303-10.
http://www.ncbi.nlm.nih.gov/pubmed/23374051?tool=bestpractice.com
A systematic analysis and modeling study reported psoriasis incidence of 30.3 per 100,000 person-years to 321.0 per 100,000 person-years, and prevalence of 0.14% to 1.99%.[4]Parisi R, Iskandar IYK, Kontopantelis E, et al. National, regional, and worldwide epidemiology of psoriasis: systematic analysis and modelling study. BMJ. 2020 May 28;369:m1590.
https://www.bmj.com/content/369/bmj.m1590.long
http://www.ncbi.nlm.nih.gov/pubmed/32467098?tool=bestpractice.com
Incidence and prevalence were relatively low in regions with young populations (e.g., south Asia and sub-Saharan Africa) and higher in regions with older populations (i.e., high-income regions).[4]Parisi R, Iskandar IYK, Kontopantelis E, et al. National, regional, and worldwide epidemiology of psoriasis: systematic analysis and modelling study. BMJ. 2020 May 28;369:m1590.
https://www.bmj.com/content/369/bmj.m1590.long
http://www.ncbi.nlm.nih.gov/pubmed/32467098?tool=bestpractice.com
In the US, a population-based cross-sectional study (using National Health and Nutrition Examination Survey data) suggested that psoriasis affects 3% of the adult population (>7.5 million adults).[7]Armstrong AW, Mehta MD, Schupp CW, et al. Psoriasis prevalence in adults in the United States. JAMA Dermatol. 2021 Aug 1;157(8):940-6.
http://www.ncbi.nlm.nih.gov/pubmed/34190957?tool=bestpractice.com
Psoriasis prevalence was similar between women and men.[7]Armstrong AW, Mehta MD, Schupp CW, et al. Psoriasis prevalence in adults in the United States. JAMA Dermatol. 2021 Aug 1;157(8):940-6.
http://www.ncbi.nlm.nih.gov/pubmed/34190957?tool=bestpractice.com
A UK population-based cohort study estimated psoriasis incidence to be 129 per 100,000 person-years.[8]Springate DA, Parisi R, Kontopantelis E, et al. Incidence, prevalence and mortality of patients with psoriasis: a U.K. population-based cohort study. Br J Dermatol. 2017 Mar;176(3):650-8.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5363241
http://www.ncbi.nlm.nih.gov/pubmed/27579733?tool=bestpractice.com
Peak incidence increases up to 39 years of age then decreases; there may be a second peak between 50 to 59 years or 60 to 69 years.[4]Parisi R, Iskandar IYK, Kontopantelis E, et al. National, regional, and worldwide epidemiology of psoriasis: systematic analysis and modelling study. BMJ. 2020 May 28;369:m1590.
https://www.bmj.com/content/369/bmj.m1590.long
http://www.ncbi.nlm.nih.gov/pubmed/32467098?tool=bestpractice.com
Psoriasis is uncommon in children. Patients presenting at a younger age are more likely to have an affected parent and to demonstrate human leukocyte antigen association.[9]Mercy K, Paller AS. Practice gaps. Prescribing patterns by dermatologists and primary care providers for pediatric psoriasis: comment on "Trends in pediatric psoriasis outpatient health care delivery in the United States". Arch Dermatol. 2012 Jan;148(1):71-2.
http://www.ncbi.nlm.nih.gov/pubmed/22250234?tool=bestpractice.com