Prevalence and clinical features of juvenile psoriatic arthritis in 425 psoriatic patients

The aim of this study was to define the prevalence and clinical features of Juvenile Psoriatic Arthritis (JPsA). According to the definition by Ansell and Bywaters, we identified the population at risk of JPsA in 425 patients with psoriasis with onset occurring before the age of 31. Among these, 85 were younger than 16 years. Five patients with JPsA were found (prevalence 1.0%). All had a family history of psoriasis and onset of skin disease in the age range 10 to 20 years. Arthritis preceded psoriasis in two cases, while in the remainder the converse occurred. The interval between the onset of cutaneous and articular involvement never exceeded 8 years. Previous studies reported the low frequency of JPsA among juvenile arthritides. Our data appear to underline the rarity of the arthritic form.