Impact of sex and age on the clinical and epidemiological aspects of childhood psoriasis: Data from a French cross-sectional multicentre study

{Background. - The prevalence of childhood psoriasis is estimated at between 0.4% and 0.7%. Clinical aspects of the diseases depend on age. The aim of this study was to investigate the clinical aspects of psoriasis according to age and sex. Patients and methods. - A cross-sectional, multicentre study of children with psoriasis was performed by investigators belonging to the Research Group of the French Society of Paediatric Dermatology. The study was conducted from April 2012 to March 2013. Inclusion criteria were age less than 18 years and clinical diagnosis of psoriasis. The children were classified into] groups by age: infants: < 2 years; children: >= 2 years and < 13 years; adolescents >= 13 years. The information collected included demographic data, clinical, epidemiological, and therapeutic aspects of the psoriasis, as well as analysis of comorbidities. Results. - Three hundred and thirteen children were included: 27 (8.6%) infants, 207 (66.1%) children, and 79 (25.2%) adolescents. Plaque psoriasis was the most frequent clinical type of psoriasis seen in children and adolescents (>41%). but it accounted for only 25.9% of psoriasis of infants (P< 0.0001). Napkin psoriasis (37.0%) and inverse psoriasis (22.2%) were the most common forms of psoriasis seen in infants and were described significantly more frequently in this group than in the two other groups (P< 0.003). Nail involvement was more common in adolescents (37.2%