Folliculitis
Folliculitis is an inflammatory reaction of the hair follicle that presents as pustules or papules on an erythematous base. It occurs more commonly in hot weather, and is not always caused by infection.
Noninfective folliculitis is usually caused by maceration, obesity, heavy sweating, contact with occlusive substances (eg oils), shaving and waxing. Folliculitis can also be caused by drugs such as corticosteroids, epidermal growth factor receptor (EGFR) inhibitors, immune checkpoint inhibitors, some antibiotics, and antiepilepticsRamdial, 20091.
Treatment of noninfective folliculitis involves general measures (eg warm compresses, antiseptic washes, clean sharp razors when shaving). Advise patients to avoid triggers.
Infective folliculitis is caused by infection, such as with Staphylococcus aureus (common, particularly in nasal carriers of this organism), Pseudomonas aeruginosa (usually acquired from hot tubs and spas), Malassezia yeasts (causing Pityrosporum folliculitis), dermatophytes, Demodex mites and herpes simplex virus.
If infective folliculitis is suspected, take a bacterial swab for cultures and susceptibility testing. Consider taking a swab for herpes simplex virus polymerase chain reaction (PCR), or requesting fungal culture (for Malassezia species), if these are suspected.
Treatment of infective folliculitis involves general measures (eg warm compresses, antiseptic washes, clean sharp razors when shaving), in addition to antimicrobial therapy guided by susceptibility results.
If S. aureus is isolated, treat as for impetigo.
For pseudomonas folliculitis, identify the source (eg hot water tank, spa) and avoid contact until the water supply has been treated. Wetsuits can also cause pseudomonas folliculitis. No specific antimicrobial or antiseptic treatment is required because the condition is usually self-limiting once exposure to the water source is avoided.
If Malassezia yeasts are identified, treat as for pityriasis versicolorVlachos, 2020.
If there is no response to treatment of folliculitis, refer for specialist advice.