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

O.A. Enigbokan1, G.O. Ogun2, A.O. Ogunbiyi1, A.O. George1

  1. Department of Medicine (Dermatology unit), University of Ibadan/University College Hospital, Ibadan, Nigeria. 
  2. Department of Pathology, University of Ibadan/University College Hospital, Ibadan, Nigeria.

Abstract

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. Munro¾s microabscesses were found in less than half of the patients biopsied. Some of the patients were found to have atypical changes.

Conclusions: 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.

Keywords: Psoriasis, Histopathology, Nigeria, Black.

Correspondence:

Dr. O.A. Enigbokan
Department of Medicine,
University College Hospital,
Ibadan, Nigeria
Email: omololuenigbokan@gmail.com
Date of Acceptance: 31st Dec., 2023
Publication Date: June 2023

Introduction

Recent reports have indicated that psoriasis is not as uncommon in our population as previously thought.1-5 Previous experience of its rarity was faced with paucity of studies on the disorder including description of its histopathologic features in this environment. Typical histopathological features of psoriasis have been described in various populations but till date, there has been no report on the histopathological features of psoriasis in West African population. As diagnosis is increasingly made, there will be an increase in demand for histopathologic support in some cases. The need to describe the histopathologic features of psoriasis in our practice setting as a future guide in pathologic diagnosis and descriptions cannot be overemphasized. In this study, we evaluated the frequency of occurrence of the various histopathologic features of psoriasis in patients from this environment and to compare with reports from other populations so as to identify the uniqueness and peculiarities in black African patients.

METHODS
The study was a cross sectional study of patients diagnosed with psoriasis at the dermatology clinic or that were admitted into the medical wards of University College Hospital, Ibadan, Nigeria between January 2015 and October 2016.

Ethical issues
Ethical clearance for the study was obtained from the joint University of Ibadan/University College Hospital, Ibadan, Nigeria Ethical Review Committee (UI/EC/ 14/0341). Furthermore, this study was conducted in compliance with the guidelines of the Helsinki declaration on biomedical research in human subjects. Confidentiality of the identity of the patients and personal health information was maintained.

Consecutive patients were recruited after obtaining an informed consent. Diagnosis of psoriasis was made on clinical grounds after examination by a dermatologist. Patients excluded from the study were patients who declined a skin biopsy, patients who had been on topical or systemic medication consistently for at least a month prior to presentation. Baseline socio demographic data and clinical history such as symptoms and onset of the disorder were documented. Skin biopsy specimen from the advancing edge of an active lesion on any involved site was taken after an informed consent was obtained and prior to commencement of anti-psoriatic medications. Sample was sent for routine fixing, sectioning, and examination under light microscopy after haematoxylin and eosin staining. The presence of the various epidermal and dermal features of psoriasis were assessed and documented in each patient using a proforma (Table 1).

Statistical analysis
Data was analyzed with SPSS 15.0 (IBM, Armonk, NY) with the frequencies of occurrence of each feature reported in percentages. A comparison of the features was done between the two sexes to identify if any differences exist. Chi square or Fischer’s test was used to analyze significance between categorical variables where appropriate while t-test was used for differences between means with significance level put at p < 0.05.