Folliculitis and Hair Follicle Inflammation

Folliculitis is inflammation or infection that develops around the hair follicle. It is commonly described as "hair root inflammation," "pimples on the body," or "post-shaving acne." While bacterial causes are the most common, Malassezia, viruses, irritation, shaving, friction, sweating, and certain medications can also lead to a similar condition.

In bacterial folliculitis, Staphylococcus aureus is a common causative agent. Pseudomonas folliculitis can develop after using hot tubs/jacuzzis that have not been properly disinfected. Malassezia folliculitis can mimic acne, presenting with itchy, similar follicular lesions, particularly on the chest, back, and shoulders.

Acne and folliculitis are not the same. Acne vulgaris can have comedones, papules, pustules, and nodules together; in folliculitis, similar papule-pustules centered on the hair follicle are more typical. Post-shave lesions can be true folliculitis or pseudofolliculitis, as discussed in P65.

Sweating, tight sportswear, friction, waxing/epilation, and shaving can all facilitate follicular inflammation in some individuals. "Pimples" on the buttocks may be folliculitis, not acne; deep, painful, recurrent abscesses should be considered in the differential diagnosis of hidradenitis suppurativa.

Diagnosis is often clinical; in recurrent or treatment-resistant cases, culture, fungal examination, or rarely biopsy may be necessary. Treatment varies depending on the cause; using antibiotics in every case of folliculitis is not appropriate and can unnecessarily increase antibiotic resistance.