Background
Pseudofolliculitis barbae (PFB) or shaving bumps is a foreign body inflammatory reaction involving papules and pustules. It primarily affects African Americans men who are genetically predisposed to pseudofolliculitis barbae because of the curvature of their hair follicles. [1] Pseudofolliculitis barbae can also affect some white men and hirsute black women. Pseudofolliculitis pubis is a similar condition occurring after pubic hair is shaved.
Pathophysiology
Two mechanisms are involved in the pathogenesis of pseudofolliculitis barbae: (1) extrafollicular penetration occurs when a curly hair reenters the skin, and (2) transfollicular penetration occurs when the sharp tip of a growing hair pierces the follicle wall.
Black men who shave are predisposed to this condition because of their tightly curved hair. The sharp pointed hair from a recent shave briefly surfaces from the skin and reenters a short distance away. Several methods of close shaving result in a hair cut below the surface. These methods include pulling the skin taut while shaving, shaving against the grain, plucking hairs with tweezers, removing hairs with electrolysis, and using double- or triple-bladed razors. The close shave results in a sharp tip below the skin surface, which is then more likely to pierce the follicular wall, causing pseudofolliculitis barbae with transfollicular penetration. [2, 3]
Pseudofolliculitis barbae has been linked to the Ala12Thr polymorphism located in the K6hf (hair follicle companion layer-specific keratin 6) gene of keratin. Winter and colleagues reported that carriers had a six-fold risk of developing pseudofolliculitis barbae. In addition, the mutation was more frequent in blacks than in others. Among the 90 black participants 36.7% were carries compared to 10.9% of non-black participants. [4]
Etiology
African Americans are genetically predisposed to pseudofolliculitis barbae because of the curvature of their hair follicles. Improper shaving techniques and the desire for a clean-shaven appearance can result in ingrown hairs via extrafollicular or transfollicular penetration.
In a study of 655 male and female police recruits in Senegal, reported risk factors for the development of pseudofolliculitis barbae include history of keloid, association with fibrosing folliculitis of the nape of the neck, use of single-blade razor, fixed-head mechanical razors, shaving against the grain, not using shaving products, and waxing. [5]
Protective factors against development of pseudofolliculitis barbae include trimming hair with clippers, use of pre-shave and post-shave products, and use of movable-head razors. [5]
Epidemiology
US frequency
An estimated 5 million black individuals have severe pseudofolliculitis barbae. [6] Up to 83% of adult black men have pseudofolliculitis barbae, particularly those who shave closely on a regular basis. [7]
Race
Pseudofolliculitis barbae is found mostly in men of African, Hispanic, Middle Eastern ancestry in whom tightly curled hair is common. [8] It is a significant problem in black men in the military and law enforcement where regulations require a clean-shaven face. [9] An estimated 45% - 83% of black individuals in the US military reported pseudofolliculitis barbae symptoms compared to 18% of white individuals. [10]
Sex
Men with facial hair comprise most patients, although hirsute women can also develop pseudofolliculitis barbae. Both sexes can develop pseudofolliculitis pubis. Common sites in black women and those of ethnic backgrounds characterized by darker skin include the pubic and axillary areas because these are more frequent sites of hair removal in this population.
Age
Pseudofolliculitis barbae affects men with facial hair (postpuberty).
Prognosis
Although usually not regarded as a serious medical problem, pseudofolliculitis barbae can cause cosmetic disfigurement. The papules can lead to scarring, postinflammatory hyperpigmentation, secondary infection, and keloid formation. No cure exists, but effective treatment is available. If the patient is able to grow a beard, the problem usually disappears (except for any residual scarring).
Patient Education
Instruct the patient to stop shaving for 3-4 weeks. This gives adequate time for the hair follicles to grow to a length where ingrown hairs will spring free.
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Pseudofolliculitis barbae on the neck of a black man.
