What’s Causing This Man’s Folliculitis Barbae?

DISCUSSION

HSV infection is common, with reports that HSV-1 affects 67% of the global population younger than 49 years.¹ Infection usually occurs in areas of the oropharyngeal mucosa, as seen with herpes gingivostomatitis and herpes labialis; the virus remains latent in the trigeminal nerve and usually reactivates with illness (ie, “cold sore”), UV radiation exposure, or trauma.^2,3 HSV-1 infections are typically diagnosed based on the prototypical presentation of multiple vesicular lesions residing on an inflammatory erythematous base.³

The use of such heuristics, however, can lead to diagnostic pitfalls, resulting in clinicians overlooking other less common cutaneous manifestations of HSV-1. Such presentations include herpes keratoconjunctivitis, herpetic whitlow, herpes gladiatorum, genital herpes (typically caused by HSV-2), eczema herpeticum, and herpes barbae.³

The term folliculitis barbae describes inflammation of the deep portions of the hair follicle in the beard area (Latin, barba, “beard”), leading to follicular pustules and erythematous papules.⁴ Etiologies of folliculitis barbae include acne vulgaris, viral infections (eg, HSV, herpes zoster virus, molluscum contagiosum), fungal infections, and bacterial infections, the latter of which—specifically Staphylococcus aureus—are the usual culprit for infectious folliculitis.^4,5 As such, empiric treatment with antibiotics is usually started in suspected cases of beard infections, and alternative diagnoses such as tinea barbae and herpes barbae are not usually considered until after the initial treatment is found to be ineffective.

Pseudofolliculitis barbae, an inflammatory condition of the hair follicles of the beard that is often a result of shaving, is another cause of folliculitis to consider in the differential diagnosis of folliculitis barbae.⁶ Asteatosis, syphilis, Sweet syndrome, syringoma, eosinophilic folliculitis, pseudolymphoma, cutaneous lymphoma, seborrheic dermatitis, impetigo, acne rosacea, allergic contact dermatitis, and irritant contact dermatitis are other conditions to consider in individuals presenting with inflammation of the beard (Table 1).

The term sycosis (Greek, sykōsis, “fig”) is also used to describe folliculitis and is synonymous with infections of the beard area. It is not to be confused with the older name sycosis barbae, which was used to describe bacterial infections of the beard.^7,8

Herpes barbae is a rare presentation of HSV-1 that is infrequently reported in the literature. Because the clinical presentation is similar to that of other types of infectious folliculitis, the diagnosis may be elusive. Thus, it is imperative for clinicians to suspect HSV infection in the differential diagnosis of folliculitis barbae.

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