PECULIARITIES OF PSORIASIS IN A BLACK AFRICAN COHORT: A HISTOPATHOLOGIC STUDY.

Background: Clinical and histopathologic observations have indicated that psoriasis is not rare in our population as previously thought. The initial rarity also led to paucity of studies on the disorder including histopathologic features in our practice setting. To date, there is no report on the histopathologic features of psoriasis indigenous to our practice environment.

Objective: To evaluate the frequency of occurrence of the various histopathologic features of psoriasis in patients from this environment and identify any peculiarities that exist in black African patients.

Methods: A cross-sectional study of patients diagnosed clinically with psoriasis at the University College Hospital, Ibadan between January 2015 and October 2016. After baseline sociodemographic data, all patients had baseline clinical examination and were offered skin biopsy after obtaining informed consent. The biopsy specimen was examined for histopathologic features of psoriasis after routine processing and staining using a pretested proforma with the frequencies of each diagnostic feature reported in percentages.

Results: Forty-four patients with plaque psoriasis were analyzed. The mean age of the patients studied was 39.84 ± 20.97 years with a male to female ratio of which was almost equal. The most consistent epidermal changes in decreasing other of frequency were acanthosis, hypogranulosis, hyperkeratosis followed by elongation of rete ridges while dermal features were dermal infiltration by inflammatory cells, and dilatation of superficial dermal vessels. Munro's microabscesses were found in less than half of the patients biopsied. Some of the patients were found to have atypical changes.

Conclusion: Histopathological features of psoriasis in the study is similar to what has been previously established universally but typical features such as Munro's micro abscesses and Kogoj's spongiform pustules are less frequently seen than expected. Atypical changes such as dermal melanophages and periadnexal infiltration by inflammatory cells may also be seen.