Clinical study of psoriasis occurring over the age of 60 years: is elderly-onset psoriasis a distinct subtype?

Background Previous studies demonstrated clinical differences of early- and late-onset psoriasis. However, epidemiological data and clinical characteristics of psoriasis occurring in geriatric patients have been rarely studied. Objective Assessment of epidemiology and clinical features of psoriasis first occurring over the age of 60 years, so-called elderly-onset psoriasis, based on clinical data. Materials and methods Among 4049 patients visiting our psoriasis clinic for the last 27 years, patients were first divided into early-(onset age before 30 years) and late-onset psoriasis (onset age after 30 years) based on our previous studies. Then, patients of late-onset psoriasis were further divided into middle age-onset group (onset age between 30 and 60 years) and elderly-onset group (onset age over 60 years). Clinical characteristics of elderly-onset psoriasis were compared with early-and middle age-onset groups. We acquired the data both by physician's assessments and patients' responses. Results Elderly-onset patients comprised 3.2% of total patients, 129 out of 4049. They have shown a lower incidence of family history (P < 0.05). The severity assessed by PASI score, body surface extent, and activity of individual lesions demonstrated that psoriasis of the elderly-onset group was generally milder compared with early-and middle age-onset groups (P < 0.05). In clinical phenotypes, the proportion of guttate type and generalized pustular psoriasis type decreased remarkably, while that of erythroderma type increased (P < 0.05). There was a significant change in the body part of origin comparing early-and middle age-onset groups (P < 0.05). The proportion of scalp increased, while that of knee-elbow and trunk decreased significantly (P < 0.05). Patients' subjective sensation of disease course improved statistically comparing early-and middle age-onset groups (P < 0.05). There was no significant change in the degree of pruritus on psoriatic lesions and nail involvement (P > 0.05). Conclusion The elderly-onset group demonstrated milder disease courses and some changes in clinical phenotypes and body part of origin compared with early-and middle age-onset groups. Therefore, it seems that patients whose onset of psoriasis was over the age of 60 years might have distinct clinical features in some clinical aspects.