Folliculitis occurs due to inflammation of the superficial hair follicle, resulting in follicularly centered papules and pustules.

The etiology of folliculitis can be variable, with bacterial, fungal (eg, candidiasis), viral, parasitic, and noninfectious causes reported. A detailed history of comorbid conditions, exposures, and medications, in conjunction with appropriate ancillary testing, can be helpful.

Specifically in children, bacterial causes such as Staphylococcus are common, as well as yeast, including Pityrosporum. Statistically, children in day care facilities and athletes are at higher risk for community-acquired methicillin-resistant S. aureus (MRSA) infection, so suspicion should be high.

Pseudomonal folliculitis has been seen in children following use of a hot tub at a pool party. A similar folliculitis in children who used recreational water facilities has been reported secondary to Aeromonas hydrophila.

Although Demodex folliculitis is very rare in children younger than age 2, one study reported a series of cases in immunocompetent children between 10 months and 5 years of age. It has also been noted in immunosuppressed children with acute lymphoblastic leukemia.

Noninfectious folliculitis may also be considered. Eosinophilic pustular folliculitis is a variant of Ofuji disease and is characterized by pruritic pustules on the scalp and peripheral leukocytosis with eosinophilia. While it has been reported frequently in infancy (eosinophilic pustular folliculitis in infancy), a childhood case was reported following bone marrow transplantation in a patient with aplastic anemia.

As expected, children who are immunosuppressed are at risk for folliculitis. One study of pediatric dermatology consultations in children with organ transplantations noted that impetigo contagiosum and folliculitis accounted for 6.2% of the cases encountered (see also immunosuppression-associated eosinophilic folliculitis).

Medication-induced folliculitis should also remain on the differential. Medications that can cause folliculitis include corticosteroids, halogens (potassium iodide, radiocontrast media), and lamotrigine.