Early-Onset Versus Late-Onset Psoriasis: A Comparative Study of Clinical Variables, Comorbidities, and Association with HLA CW6 in a Tertiary Care Center

BACKGROUND: Psoriasis is a chronic inflammatory diseaseresulting from a complex interplay of genetic and environmental factors affecting the skin, nail and joints. Two distinct types of psoriasis are said to exist (i) early onset psoriasis (EOP), beginning before the age of 40 years and (ii) late onset psoriasis (LOP), beginning ≥40 years; with the presence of Human lymphocyte antigen (HLA) Cw6, present in majority of patients with early onset. Several studies demonstrated clinical and genetic differences between EOP and LOPamong European and East Asian populations. Lack of similar study in the Indian population has prompted us to undertake the present work. AIMS AND OBJECTIVES: (i) To compare the clinical patterns of early onset and late onset psoriasisin patients attending the Dermatology outpatientdepartment (OPD) and admitted in the in-patient department (IPD). (ii) To analyze the association age of onset with presence of HLA Cw6. MATERIALS AND METHODS: It was an institution-based, descriptive, cross-sectional study. Consecutive patients with psoriasis at the OPD and IPD of the department of Dermatology during the study period, were recruited in the study after obtaining informed consents. Detailed history was obtained regarding the disease, co-morbidities and complications. Through physical examination was carried out, PASI was calculated and blood samples were drawn fromconsenting adult patients (age>/=18 years) to study the presence of Cw6. RESULTS: The study population (n=250) wasbroadly divided into “Early onset psoriasis(EOP)” (n=138) and Late onset psoriasis (LOP)” (n=112).Significant higher occurrence of positive family history, nail involvement and koebnerization were found in EOP, but such differences were absent considering the types, patterns, joint involvement, severity and HLACW6 positivity. CONCLUSION: This study supports the concept of two subtypes of psoriasis based on age of onset showing different clinical and evolutionary features.