Psoriasis in Kaduna, North-West Nigeria: A twenty-year experience

Background: Psoriasis is a chronic inflammatory skin disease which may be associated with joint, cardiovascular, metabolic or psychiatric disease. Countries in North America, Northern Europe and Australia have the highest burden of disease while those in Asia, South America and Africa, the lowest. We report our experience of psoriasis in Kaduna, Nigeria, over 20 years and compare this with previous reports in the same area and in other parts of Nigeria and Africa. Objective: To report the relative incidence, clinical presentation, severity and associations of psoriasis seen over 20 years. Methods: A retrospective review of records of patients with psoriasis seen at two outpatient dermatology clinics in Kaduna, North-West Nigeria, over 20 years. Results: Diagnosis of psoriasis was made in 218 of 39,037 (0.6%) patients with new skin disease: Mean age 35.2 years, range (6 months to 80 years), 60% <40 years, males constituted 64.2%. Mean age of onset was 30.5 years with a quarter developing psoriasis before age 20 and 71.4% before 40 years. Psoriasis presented earlier in females than males (mean age of onset 27.6 vs. 32.2 years, P= 0.052) but was less severe. Psoriasis types were: Plaque 88.1%, guttate 6%, erythrodermic 4.6% and sebopsoriasis 0.9%. Only four patients had joint disease and other associations were infrequent. Overall, 80.3% had mild psoriasis and 13.2% had a family history. Conclusion: Psoriasis remains a rare and mild disease in Kaduna and is infrequently associated with joint and other systemic disease but similar in other respects to the condition elsewhere.