CLINICAL REPORT
1225 Advances in dermatology and venereology ActaDV Acta Dermato-Venereologica ActaDV
Autoimmune Disease in Children and Adolescents with Psoriasis: A Cross-sectional Study in Denmark
Christoffer BLEGVAD 1, 5, Alexander EGEBERG 1, Tilde E. TIND NIELSEN 1, 5, Gunnar H. GISLASON 2 – 4, Claus ZACHARIAE 1, Anne-Marie NYBO ANDERSEN 5 and Lone SKOV 1
1
Department of Dermatology and Allergy, 2 Department of Cardiology, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup,
3
The Danish Heart Foundation, 4 The National Institute of Public Health, University of Southern Denmark, and 5 Section of Social Medicine, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
Psoriasis is an immune-mediated inflammatory disease, which, in studies among adults, have been shown to cluster with autoimmune disease. The aim of this cross-sectional register study was to examine possible associations between 9 pre-selected autoimmune diseases and psoriasis in children and adolescents. The study population consisted of all individuals living in Denmark, age under 18 years on 31 December 2012. A total of 1,925 children and adolescents with psoriasis and 1,194,712 without psoriasis were identified. Psoriatic arthritis( adjusted odds ratio( OR) 10.08; 7.97 – 12.74), rheumatoid arthritis( adjusted OR 6.61; 2.75 – 15.87) and vitiligo( adjusted OR 4.76; 1.71 – 13.20) showed strong associations with psoriasis. In addition to increased risk of selected autoimmune diseases, the presence of psoriasis was associated with increased risk of multiple concurrent autoimmune diseases compared with children and adolescents with out psoriasis. Clinicians should be aware of extracutaneous symptoms when treating children and adole scents with psoriasis.
Key words: psoriasis; autoimmune disease; children; adolescents; comorbidity.
Accepted Jul 5, 2017; Epub ahead of print Jul 6, 2017 Acta Derm Venereol 2017; 97: 1225 – 1229.
Corr: Christoffer Blegvad, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, Kildegårdsvej 28, DK-2900 Hellerup, Denmark. E-mail: christoffer. blegvad. 01 @ regionh. dk
Psoriasis is chronic inflammatory skin condition with an autoimmune pathogenetic component and a strong, but complex, genetic inheritance( 1, 2). The estimated prevalence of psoriasis in the western world is 3 – 4 % in adults and 0.4 – 1.37 % in children and adolescents( henceforth“ children”)( 3 – 7). The prevalence rate increases approximately linearly, from 0.12 % at an age of 1 year to 1.24 % at 18 years of age( 3). Incidence of psoriasis is bimodal, with a large peak at 16 – 22 years and a smaller peak at 57 – 60 years, probably reflecting different disease entities( 8). The disease can be debilitating for patients due to pruritus and visible disfiguration resulting from presence of red plaques with silvery scales, in turn leading to decreased quality of life( 9). In addition, patients with psoriasis have an increased risk of several comorbidities, such as cardiovascular disease, metabolic syndrome, and psoriatic arthritis( 10 – 18).
Studies suggest that some of the comorbidities and associated risk factors that are seen in adults with psoriasis may also be present in children with psoriasis. Indeed, studies have suggested increased presence of arterial hypertension, metabolic syndrome, and autoimmune diseases, including rheumatoid arthritis and Crohn’ s disease, in paediatric psoriasis( 3, 19 – 28).
Autoimmune diseases, such as rheumatoid arthritis and inflammatory bowel disease( IBD), have a profound negative effect on quality of life( 29, 30). They are therefore a potential additional disease burden to keep in mind when treating patients with psoriasis. Autoimmune diseases display a heightened immune response against the person’ s own tissue, cells, and cellular components, such as DNA, keratin, or, for psoriasis, a melanocytic autoantigen. A recent study confirmed that psoriasis shares genetic susceptibility loci with a range of autoimmune diseases including IBD( 2, 31). In order to further examine the risk of concomitant autoimmune disease and clustering of autoimmune diseases in children with psoriasis compared with healthy controls, we conducted a cross-sectional study using the total paediatric population in Denmark.
METHODS Population
All inhabitants under the age of 18 years who were alive and resident in Denmark on 31 December 2012 were identified. All residents in Denmark are assigned a unique personal 10-digit identification number at birth or immigration, which enables linkage on the individual level between different Danish administrative registers. This study used data from the Danish Civil Registration System, the Danish National Patient Register, and the Danish National Prescription Registry. Data on age, sex, vital- and migration status were available from the Danish Civil Registration System( 32). Established in 1978, the Danish National Patient Register contains information on all hospital-based inpatient and, since 1994, outpatient consultations. Diagnosis are recorded according to the International Classification of Diseases, 8 th Revision( ICD- 8) until 1994, and the 10 th Revision( ICD-10) thereafter( 33). Information on psoriasis and a number of autoimmune diseases was obtained from here. The Danish National Prescription Registry contains detailed information on the individual level on every Danish pharmacy-dispensed medication since 1994, coded
This is an open access article under the CC BY-NC license. www. medicaljournals. se / acta Journal Compilation © 2017 Acta Dermato-Venereologica. doi: 10.2340 / 00015555-2743 Acta Derm Venereol 2017; 97: 1225 – 1229