Description

• Foreign body inflammatory reaction from an ingrown hair resulting in the appearance of papules and pustules. This is found mainly in the bearded area (barbae) but may occur in other hairy locations such as the scalp, axilla, or pubic areas where shaving is done (1).
• A mechanical problem: extrafollicular and transfollicular hair penetration
• System(s) affected: skin/exocrine
• Synonym(s): chronic sycosis barbae; pili incarnati; folliculitis barbae traumatica; razor bumps; shaving bumps; tinea barbae

Epidemiology

• Predominant age: postpubertal, middle age (14 to 25 years)
• Predominant sex: male > female (can be seen in females of all races who wax/shave)

Incidence

• Adult male African Americans: unknown
• Adult male whites: unknown

Prevalence

• Widespread in Fitzpatrick skin types IV to VI (darker complexions) who shave
• 45–83% of African American soldiers who shave (1)

Etiology and Pathophysiology

• Transfollicular escape of the low-cut hair shaft as it tries to exit the skin is accompanied by inflammation and often an intraepidermal abscess.
• As the hair enters the dermis, more severe inflammation occurs, with downgrowth of the epidermis in an attempt to sheath the hair.
• A foreign body reaction forms at the tip of the invading hair, followed by abscess formation.
• Shaving too close
• Plucking/tweezing or wax depilation of hair may cause abnormal hair growth in injured follicles.

Genetics

• People with curly hair have an asymmetric accumulation of acidic keratin hHa8 on hair shaft.
• Single-nucleotide polymorphism (disruption Ala12Thr substitution) affects keratin of hair follicle.

Risk Factors

• Curly hair
• Shaving too close or shaving with multiple razor strokes
• Plucking/tweezing hairs
• South Mediterranean/American, Middle Eastern, Asian, or African descent (skin types IV to VI)

General Prevention

• Prior to shaving, rinse face with warm water to hydrate and soften hairs.
• Use adjustable hair clippers that leave very low hair length above skin.
• Shave with either a manual adjustable razor at coarsest setting (avoids close shaves), a single-edge blade razor (e.g., Bump Fighter), a foil-guarded razor (e.g., PFB razor), or electric triple “O-head” razor.
• Empty razor of hair frequently.
• Shave in the direction of hair growth. Do not overstretch skin when shaving.
• Use a generous amount of the correct shaving cream/gel (e.g., Ef-Kay shaving gel, Edge shaving gel, Aveeno therapeutic shave gel, Easy Shave medicated shaving cream).
• Daily shaving reduces papules/pruritus.
• Regular use of depilatories

Commonly Associated Conditions

• Keloidal folliculitis
• Pseudofolliculitis nuchae