How common is psoriasis
How prevalent is psoriasis and PsA in the general population?
Epidemiologic studies suggest that the prevalence of psoriasis is approximately 2% to 3%. Whites are affected (two times) more often than other ethnic groups. Men and women are equally affected. Peak incidence is in the 4th decade of life. Historical estimates of inflammatory arthritis accompanying psoriasis range from 7% to 42%. A recent study showed that among patients with psoriasis seen in academic medical centers (nearly one-quarter of them were on biologic therapy), 30% will have rheumatologist-confirmed PsA. This same study showed that 15% of patients with psoriasis followed by dermatology had undiagnosed PsA, and hence benefitted from referral to rheumatology.