[Pseudofolliculitis barbae in police students in Dakar: epidemiological and clinical aspects, and associated risk factors].

Background: Pseudofolliculitis barbae (PFB) is a chronic inflammatory skin disease favoured by shaving. It is particularly common among black Africans belonging to certain socio-professional categories who are obliged to shave. Its aesthetic and professional damage is very significant. However, very few data are available for this condition, especially in Sub-Saharan Africa.

Objective: To determine the epidemiological and clinical aspects, and the risk factors associated with the occurrence of PFB in Dakar.

Population and methods: This was a descriptive cross-sectional study conducted in March 2019, including 655 police students at the National Police Academy in Dakar, all of African descent and with curly hair, who were required to shave weekly and agreed to participate in this study. The diagnosis of PFB was clinically based. Data analysis was processed using Epi-info version 6.0 software. Pearson's chi-square test was used for bivariate analysis with a significance threshold of p < 0.05. The Odds Ratio, with its 95% confidence interval, was used to determine the risk factors.

Results: Among the 655 officers, 254 had PFB, with a prevalence of 38.8%. The prevalence of PFB was 43.7% in men (242 men out of 554) and 11.9% in women (12 women out of 101). The average age of patients with PFB was 26.80 years (± 2.59), ranging from 22 to 36 years. The age of onset of PFB was between 18 and 20 years for the majority (39.8%), with a mean age of onset of 22.2 years (± 3.6). PFB lesions were pruritic in 84.6% of cases, papular in 96.8%, and/or pustular in 60.2%. The submandibular region was the most affected site (69.8%). Complications were noted in 90.1% of cases in the form of post-inflammatory hyperpigmentation (87%) and keloid scars (3.1%). The risk factors associated with PFB were male sex (p<0.0001; OR=5.7; CI95% [3.07-10.75]), family history of PFB (p<0.0001; OR=5; CI95% [3.35-7.37]), keloid-prone skin (p<0.0001; OR=2.9; CI95% [1.63-4.96]), association with acne keloidalis nuchae (p<0.0001; OR=8.8; CI95% [5.55-14.08]), use of a single-blade razor (p<0.0001; OR=2.5; CI95% [1.69-3.70]), use of a fixed-head razor (p<0.0001; OR=1.8 CI95% [1.28-2.77]), shaving against the grain (p<0.0001; OR = 6.3; CI95%= [4.33-9.08]), non-use of shaving products (p = 0.009; OR = 1.5; CI95%= [1.06-2]) and waxing (p<0.004; OR=2.7; CI95% [1.33-5.77]). On the other hand, the use of clippers (p<0.0001; OR = 0.5 CI95% [0.33-0.65]), pre-shave products (p<0.0001; OR = 0.4 CI95% [0.29-0.61]) and the use of razors with movable heads (p<0.0009; OR = 0.2 CI95% [0.17-0.35]) were protective factors against PFB.

Conclusion: Our study confirms the high incidence of PFB in this population of black men of African descent. A genetic abnormality revealed by shaving must be evoked in the occurrence of PFB. Further genetic and immunohistochemical studies would be needed to support this hypothesis.