Background Childhood-onset psoriasis (COP), a distinct clinical entity, may be associated with HLA-Cw6 positivity and metabolic and cardiovascular complications. There is some evidence that HLA-Cw6 positivity is associated with more extensive or severe disease and that positivity is lower in Asian patients than in Caucasians. We describe the clinical profile, prevalence of the HLA-Cw6 allele, metabolic syndrome (MetS) and vitamin D deficiency in Indian patients with COP.

Methods In this cross-sectional hospital-based study over 15 months (June 2010–August 2011), 108 consecutive patients with disease onset ≤16 years were enrolled. Demographic, clinical and laboratory data were collected. Patients were categorised as children with COP (CCOP; n=69) or adults with COP (ACOP; n=39). Disease severity was assessed using body surface area (BSA) involved and Psoriasis Area and Severity Index (PASI) score.

Results The most common morphological type was chronic plaque psoriasis; follicular psoriasis was seen only in children. Adults with disease onset in childhood, when compared with CCOP, had later disease onset (11.0±4.0 vs 6.9±3.8 (mean±SD) years; p<0.0001) of greater severity (p=0.021) based on BSA involved. PASI scores were, however, similar in ACOP and CCOP. Body mass index was not associated with disease severity. Of the 83 who underwent HLA-C typing, 46 (55.4%) were positive; positivity was associated with guttate lesions (p=0.031), scalp involvement (p=0.004), greater BSA involvement (p=0.002) and higher PASI scores (p=0.013). Vitamin D deficiency, obesity and MetS were present in 77.4%, 10.7% and 14.5% of patients, respectively.

Conclusions Among Indian patients, CCOP have earlier disease onset than ACOP. HLA-Cw6 was associated with guttate psoriasis, scalp involvement and disease severity. Vitamin D deficiency was common.