Pseudofolliculitis barbae

Introduction

Pseudofolliculitis barbae (PFB) (OMIM 612318) is a chronic, non-infectious inflammatory disorder induced by re-entry of curved hair shafts into the skin following hair removal. After shaving, the sharp tip of curved hair shafts can re-enter the skin a short distance from the follicle after exiting the skin surface (extrafollicular penetration) or by piercing the follicular wall without emerging from the skin surface (transfollicular penetration), resulting in a foreign body inflammatory reaction. It is most prevalent in men of African ancestry (affecting between 45% and 83% of Black men); however, it can be found in all races and genders with a 50-fold increased risk for curly hair. A substitution mutation in the 1A-helical segment of the hair follicle-specific keratin 75 (formerly K6hf) was found to be associated with a sixfold increased risk for PFB. PFB is characterized by inflammatory papules and pustules, and can result in postinflammatory hyperpigmentation, permanent scarring, or even keloid formation.

Management Strategy

PFB is a clinical diagnosis, relying on careful inspection and history taking to rule out other diagnoses. Clinicians should obtain pertinent history such as shaving frequency, shaving tools, chronicity, history of keloids, past treatment regimens, and current facial product use. Differential diagnosis includes acne vulgaris, traumatic folliculitis, granulomatous diseases such as sarcoidosis, hidradenitis suppurativa, and bacterial folliculitis. Acne vulgaris can be distinguished from PFB by the presence of comedones as well as lesions in non-hair–bearing areas. Traumatic folliculitis can be identified by a history of aggressive shaving techniques. Folliculitis is an infectious cause of follicular pustules most commonly caused by Staphylococcus aureus .

Complete resolution of PFB is possible if shaving is completely discontinued. Allowing beard hair to grow at least 1 cm in length permits spontaneous release of embedded hairs and resolution of active lesions in 1–2 months. Patients should be informed that symptoms from PFB are likely to be exacerbated over the course of the first week as the curved hairs are initially able to re-enter the skin. For symptomatic control during this time, warm water compresses for 10–15 min three times daily may offer some benefit. The addition of a low-potency topical corticosteroids (e.g., desonide lotion) for approximately 2 weeks can also help to alleviate symptoms. To avoid corticosteroid-induced atrophy and hypopigmentation, it is important to consider a regimen that includes rest periods between treatments if used beyond 2 weeks. In rare instances, a short course of oral steroids can be considered in cases with severe pain, erythema, and inflammation that does not subside with use of warm compresses and topical corticosteroids. If indicated, a 40–60 mg taper of prednisone for 5–10 days can assist with symptomatic control.

Many individuals suffering from PFB may be unable to stop shaving completely due to a variety of reasons, ranging from personal preference for a clean-shaven appearance to occupational requirements. Waivers permitting facial hair growth in PFB patients who have occupational grooming requirements can assist those who would otherwise be forced to shave regularly. Individuals who prefer a clean-shaven appearance should be educated on acceptable shaving techniques. Recommended steps include: (1) prewashing with a hydrating skin cleanser using circular motions with warm water and gentle scrubbing tools to soften the beard and dislodge embedded hair shafts; (2) using a generous amount of shave gel or cream in order to smoothen the glide of the razor; (3) shaving in the direction of hair growth using a clean, sharp razor (e.g., Gillette Skin Guard, a 2-blade razor separated by a skin guard and lubricating strips on the front and back of the razor; Gillette Fusion ProShield, a 5-blade razor with a lubricating strip on the front and back of the cartridge; or Bumpfighter, a single blade razor with a polymer coating and foil guard) while being sure to use light strokes, not pulling the skin taut; (4) using a moisturizing aftershave preparation; and (5) using a low-potency topical corticosteroid for inflamed areas or a topical antimicrobial (e.g., fixed combination benzoyl peroxide–clindamycin gel). Patients should be advised to avoid plucking or tweezing of embedded hairs and depend on gentle hair releasing techniques. As an alternative to manual razor shaving, triple-O electric clippers can be used at a setting that maintains beard hair length at approximately 1 mm, which has been shown to prevent both transfollicular and extrafollicular penetration.

Chemical depilatories, such as barium sulfide and calcium thioglycolate, weaken disulfide bonds in the hair shaft and can be considered as an alternative to shaving. These products are applied every 1–3 days to a moistened beard for 5–15 min and then removed with a blunt edge. However, irritant contact dermatitis is a limitation of chemical depilatories (especially of barium sulfide powder); this can be minimized by recommending cream formulations containing calcium thioglycolate, monitoring contact time to avoid stinging or burning, and application of emollients immediately postusage.

Topical eflornithine hydrochloride, which inhibits hair growth via irreversible inhibition of ornithine decarboxylase, has also shown to benefit patients with PFB. Topically applied eflornithine hydrochloride cream 13.9% two times daily used in conjunction with laser hair removal has been shown to be more effective than monotherapy with laser alone.

Laser hair removal is an effective long-term therapy for PFB. Given the increased risk for complications in patients with darker complexions, careful selection of a laser device and appropriate settings for a given skin phototype is essential. The long-pulsed 1064 Nd:YAG is considered the safest laser modality for hair removal in Fitzpatrick skin types V and VI owing to its lower incidence of adverse effects. Other laser technologies that have been used in the treatment of PFB in darker skin types include the 800–810-nm diode and the 650 microsecond 1064-nm Nd:YAG laser. The 755 nm Alexandrite laser was found to be superior to intense pulse light in the treatment of PFB in a split face study involving subjects with Fitzpatrick skin phototypes II–IV. Complete resolution requires multiple sessions (typically ranging from 6 to 8 sessions depending on device, settings, and clinical features).

Electrolysis is largely not recommended for patients with PFB due to its limited efficacy and lack of practicability in treating large areas of involvement. Surgical depilation has the potential to cause scarring, including keloids, and is therefore not advised in the opinion of this author (AFA).

Nightly application of topical retinoids (i.e., tazarotene, tretinoin, or adapalene) and other keratolytic agents, such as glycolic acid or monthly chemical peels, can facilitate reductions in follicular penetration via exfoliation. Additional benefits include improvement in the appearance of hyperpigmentation.

A recent case report identified photodynamic therapy as a potential treatment modality for recalcitrant PFB. This novel therapy is the only one of its kind in the literature. More research needs to be done to determine its clinical applicability in patients with PFB.