Dermatology

Pseudofolliculitis Barbae (pili incarnati, shaving bumps)

Pseudofolliculitis barbae, pili incarnati, shaving bumps

Are You Confident of the Diagnosis?

Depending on the patient’s predisposition for pseudofolliculitis barbae (PFB), various hair removal processes may produce short, sharp, and pointed hairs that penetrate the skin either in an extra- or transfollicular manner. The ingrowing hairs initiate a foreign body reaction, producing erythematous papules and pustules (“pseudofolliculitis”) that may heal with or without scarring and may produce keloid formation. This process is historically thought to be limited to facial hair region “ barbae” of males but may also be seen in females that shave as a result of facial hirsutisim or that shave the axilla or bikini regions.

The PFB incidence in the black population is 82% versus 18% in Caucasian individuals. A lower percentage of PFB-affected individuals are black (7%) and Caucasian women (3%), who noted PFB symptoms after shaving secondary to hirsutisim or grooming in the groin and/or the axilla.

What you should be alert for in the history

The history will reveal a papulopustular reaction following shaving or other hair removal process such as facial waxing where hairs are tramatically removed. A family history of similar shaving difficulty is almost universally positive in the father, but mothers may have similar reactions when pulling or plucking facial hairs, or may have a similar reactive process in the axilla and/or the bikini area when shaving.

Characteristic findings on physical examination

Characteristic findings on physical examination include ingrowing hairs in polymorphic stages of development from erythematous papules, to pustules, to scaring or keloid formation (Figure 1, Figure 2). Background postinflammatory hyperpigmentation can be quite extensive in the affected area.

Figure 1.

Clinical PBF in an Afro-American patient.

Figure 2.

Clinical PFB in a Caucasian patient.

Expected results of diagnostic studies

Histopathologic features may range from an acute abscess to a foreign body reaction. There are no universally available genetic tests. Among imaging studies. on episcope exam hairs can be observed penetrating the adjacent perifollicular skin in an extrafollicular or transfollicular manner.

Diagnosis confirmation

Differentiation from folliculitis, which may require systemic antibiotics, should be considered when there is involvement of other areas that are not being treated with a hair removal process. In the presence of patients with hypertrophic or keloidal scars, a detailed clinical inspection with potential skin biopsy if lesions are not follicular-based should be considered to rule out sarcoidosis.

Who is at Risk for Developing this Disease?

Pseudofolliculitis barbae occurs predominantly in black males (Figure 1). PFB is usually far less severe in Caucasian males and as a result is often overlooked or underdiagnosed (Figure 2). Black individuals have a higher propensity of developing PFB due to their genetic predisposition for curly hair, which inherently possesses a much higher risk of growing back into the skin than straight or wavy hair. The PFB process is, however, not gender-dependent nor restricted to the face, but can occur in any skin region once regular shaving, plucking, or other traumatic means of hair removal are instituted

What is the Cause of the Disease?

Etiology

PFB is an unusually complex disease process whose etiology, besides shaving as the mechanical condition sine qua non, involves several genetic risk factors. One of these risk factors seems to be a defect in a keratin gene. The potentially hair-destabilizing polymorphism observed in the K6hf gene, also requires a mechanical stress like shaving to become activated. Apparently, the effects of both risk factors are then modulated by likewise genetically determined traits such as hair type and patterns, which may either lead to an aggravation or an attenuation of the PFB phenotype. Facial hair patterns have also been identified as an additional genetic factor involved in the PFB process. Normally, the direction of beard hair growth is caudal. Cephalic directed hair patterns or those in whorls or small eddies have been found to initiate localized PFB after shaving.

Pathophysiology

Recent studies have demonstrated a single nucleotide polymorphism in which a G→A transition in the Ala12 codon of the K6hf gene takes place in patients with the PFB phenotype. There are multiple reasons that may account for this unusual spread of the K6hf gene defect. First, it is evident that compared with the known plethora of disfiguring and disabling keratinopathies, PFB represents a distinctly minor health problem. Based solely on its symptoms, there is certainly only a negligible social pressure against its spread. Only a few examples are known for distressing and discriminating situations related to PFB, ie, for Afro-American men enrolled in the US Military, where a rigid grooming code requires clean-shaven faces and the resulting “razor bumps” are a source of much misunderstanding and social unrest.

Otherwise, affected men have the options of either growing a beard ,hich completely circumvents the outbreak of the disorder, or substantially minimizing PFB symptoms by improvising less traumatic shaving “with the grain,” using razors that avoid both the formation of sharp hair tips or retraction of the cut hair underneath the skin. More importantly, however, it has to be taken into consideration that in the female population with a generally low shaving rate, the Ala12Thr polymorphism remains essentially dormant and is thus propagated without knowledge. Collectively, all of these factors contribute to the relatively high incidence of the deleterious K6hf gene defect and its maintenance in the human population.

Intuitively then, one questions how the K6hf Ala12Thr polymorphism promotes PFB. The basic follicular anatomy helps us understand the process. The hair shaft is surrounded by the outer root sheath (ORS), the companion layer, and the inner root sheath (IRS). Cells of the companion layer display a particularly striking concentration of prominent intermediate filament bundles on the side facing the outer Henle cells of the IRS, to which they are tightly connected by numerous desmosomes. This suggests that the companion layer/IRS complex constitutes a functional tissue unit that tightly surrounds the hair shaft and serves to guide and stabilize the ascending hair.

It is conceivable that IF-destabilizing mutations in the K6hf keratin may disturb both the mechanical integrity of companion layer cells and their firm attachment to the IRS, and thus lead to a functionally compromised companion layer/IRS unit. This compromised unit may no longer be able to tightly guide and protect the hair on its movement to the skin surface. Importantly, most disruptive keratin mutations remain essentially unremarkable as long as the corresponding tissue is not mechanically traumatized.

In the case of the PFB-associated hair follicle, both pressure and traction exerted on the skin by regular and close shaving may represent the mechanical stress that activates the deleterious nature of the K6hf Ala12Thr polymorphism and results in destabilized pointed hairs in the hair channel. These hairs subsequently run a high risk of either getting trapped while still in the hair channel or leaving the follicular orifice in a less than optimal manner and consequently growing back into concave skin areas of the submental or submandibular region (Figure 3).

Figure 3.

Sharp hairs leaving the follicular orifice and growing back into the skin.

It is evident that the hair-destabilizing effect of the K6hf Ala12Thr polymorphism should generally be more efficient in promoting PFB in the presence of curled rather than straight hair. It is therefore possible that the combination K6hf Ala12Thr/straight hair may remain phenotypically unremarkable in particular if the submental and submandibular skin regions exhibit horizontally oriented hairs that are less able to grow back than caudally oriented hairs. Those apparently not unusual hair patterns may partially account for the relative high number of Caucasian individuals exhibiting the K6hf Ala12Thr substitution in the absence of PFB symptoms.

Systemic Implications and Complications

None

Treatment Options

Since PFB is induced by removing hair (shaving, pulling, plucking, waxing etc.) one simple treatment would be to allow the hair to grow out past a length that would allow it to remain on the surface and not curve back into the skin. If this option is considered, one must constantly lift the embedding distal sharp hair ends with brushing. The hair that is presently embedded should be lifted, not plucked or removed, as this can initiate the process deeper down in the follicle.

If a clean-shaven appearance is required or preferred, treatment involves the following considerations:

-The hair that is presently embedded should be lifted, not plucked or removed, as this can initiate the PFB process deeper down within the follicle.

-Those who desire to continue to shave with a razor should be educated in the use of hair clippers so that hair will be left at a length that will not regrow back into the skin. The affected area should be gently brushed against the grain prior to clippin, to loosen hairs that have been embedded.

--Retinoic or azelaic acid may enhance proper follicular development and aid postinflammatory hyperpigmentation. Topical desonide can be implemented in a short 1-2 week course for acutely inflammed papular eruptions.

-Oral tetracyclines are not required as this is a sterile foreign-body reaction and not a pyoderma, however, they may help decrease the inflammatory response Topical antibiotics like clindamycin, have not shown to be of much value added as they are with acne vulgaris.

- Several longer wavelength long pulsed lasers likely alexandrite, 810 nm diode, and the ND:YAG, when combined with an epidermal protective chilling device, can be used to produce dramatic long-lasting remission.

Optimal Therapeutic Approach for this Disease

Shaving Instructions

Step 1. Prepare the skin with a 2-minute wash

Washing with a gentle scrub and warm water before shaving is a simple way to cleanse the skin and significantly improve the quality of the shaving experience. When oil, dirt, perspiration and debris build up around the hair follicles, water penetration into the hair can be inhibited and prevent the razor from cutting optimally. Using a gentle scrub before shaving removes excess oils, dirt, dead skin cells and may free trapped or embedded hairs that have started to grow into the skin and initiate a PFB reaction.

Step 2: Prepare the hair with a hydrating gel for 2 minutes

Allowing water to penetrate the hair is essential for reducing the challenges associated with PFB because dry hair is difficult to cut. In fact, dry hair can have the same strength as a copper wire of similar thickness. Shaving without allowing the hair time to soften can cause excessive pulling on the hair, poor blade engagement resulting in sharper hair tips, damage to the blade and ultimately, promote the development of PFB as well as the associated development of postinflammatory hyperpigmentation. When hair is hydrated, it swells and has up to 40% less tensile strength allowing it to be cut more easily, with less pulling and less potential for sharp angled ends.

Step 3: Shave

Once skin and hairs are prepared for shaving, cut hairs with a high-quality razor using gentle strokes. The razor should be rinsed frequently to prevent the build-up of cut hairs between the blades.

Step 4: Maintain and prepare the skin and hair for the next shave

Apply an antiinflammatory moisturizer to a wet face and let it absorb for 1 minute then pat dry.

Shaving can unknowingly remove cells of the stratum corneum, as well as natural moisturizers. If this moisture barrier is not restored, patients can develop dry, tight and irritated skin. Using a high-quality moisturizing after-shave lotion with emollients, hydrating humectants, and antiinflammatory aloe can enhance the skin’s protective moisture barrier, rehydrate the skin and hair, and decrease the inflammatory reaction in the skin that can lead to postinflammatory hyperpigmentation.

Just a few minutes of preparation before, during, and after shaving, can optimize one’s shaving experience. Adherence to this shaving procedure can result in a more comfortable and less irritating shave and the reduction of PFB difficulties associated with daily shaving.

Treatment

Minocycline100mg orally twice a day until inflammatory papules are cleared (3-6 months) in conjunction with azelaic acid apply to the affected area topically at night prior to bed.

Referral for laser therapy to the submandibular region, which is classically the most problematic, in conjunction with the above steps for shaving and therapy.

Patient Management

I recommend a 90-day follow-up to check progress. If PFB continues despite treatment or if there is associated scarring, I would suggest a prompt referral for laser therapy.

Unusual Clinical Scenarios to Consider in Patient Management

Cyclosporin-induced hyperplastic pseudofolliculitis has been reported in renal transplant recipients.

What is the Evidence?

Winter, H, Schissel, D, Parry, D, Smith, T, Liovic, M, Lane, E. "An unusual Ala12Thr polymorphism in the 1A Alpha-Helcal segment of the companion layer-specific keratin K6hf: evidence for a risk factor in the etiology of the common hair disorder pseudofolliculitis barbae". J Invest Dermatol. vol. 122. 2004. pp. 652-7.

(An unusual single nucleotide polymorphism, which gives rise to a disruptive Ala12Thr substitution in the 1A alpha helical segment of the companion layer-specific keratin k6hf of the hair follicle, is partially responsible for the phenotypic expression and represents an additional risk factor for PFB).

Ross, EV, Evans, LA, Yeager, JK. "Pseudofolliculitis barbae associated with an unusual hair whorl". Cutis. vol. 51. 1993. pp. 107-8.

(A white patient with unilateral PFB in the inframandibular region, the first such case associated with a hair whorl, is described.)

Crutchfield, CE. "The causes and treatment of pseudofolliculitis barbae". Cutis. vol. 61. 1998 Jun. pp. 351-6.

(A review of the pathogenesis of PFB with a systematic approach to therapy.)

Perry, P, Cook-Bolden, F. "Defining pseudofolliculitis barbae in 2001: a review of the literature and current trends". J Am Acad Dermatol. vol. 46. 2002 Feb;. pp. S113-9.

(A review of the history, incidence, clinical manifestations, dermatopathology, prevention and treatment of PFB.)
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