Types

Several different forms of folliculitis are described:

• infectious causes
  • bacteria Yeasts Fungi Virus Parasites Environmental folliculitis Folliculitis due to skin diseases Other forms (1)
    • Staphylococcal folliculitis
      • most common form of bacterial folliculitis (1)
        
        
    • Hot tub folliculitis
      • can present as red spots and pustules on the trunk
      • due to an infection with Pseudomonas aeruginosa from improperly sanitised hot tubs or spas
      • caused by Pseudomonas aeruginosa contamination of undertreated water in saunas or whirlpools (2)
        
        
    • Gram negative folliculitis
      • rare pustular facial eruption, usually following antibiotic treatment of acne
      • gram-negative pathogens including Klebsiella, Enterobacter, and Proteus species may replace the gram-positive flora on facial skin, nasal mucous membranes, and neighbouring areas, causing gram-negative folliculitis and boils (3)
    • Pityrosporum folliculitis
      • presents as an itchy acne-like rash on the back and chest of young adults
      • most commonly, it is caused by Pityrosporum ovale (also called Malassezia).
    • Tinea capitis or ringworm of the scalp is a fungal infection involving the hair follicles of the scalp
      • generally, it presents as scaling and hair loss, but may cause more severe inflammation or folliculitis in some people.
    • Herpes simplex virus or cold sore virus
      • occasionally cancause folliculitis
      • most commonly it affects men who experience recurrent localised facial herpes simplex infections and shave with a razor.
    • Demodex folliculitis
      • presentation similar to rosacea
      • caused by the hair follicle mite demodex
      • occurs on the faces of people whose immune system has been suppressed, usually with medication.
    • Mechanical folliculitis
      • caused by chronic frictional factors
      • occurs frequently in men or women who shave their faces or legs with a razor, particularly if they do so against the direction of the hairs
      • occasionally, it may also be associated with the wearing of tight pants or obesity.
    • Occlusion folliculitis
      • caused by blockages of the follicles as a result of exposure to topical products such adhesives, oil, moisturisers, greases and ointments that cause swelling of the skin of the hair follicle opening
    • Chemical folliculitis
      • caused by exposure to certain topical products such as coal tars and the overuse of topical medications such as corticosteroids
        • particularly on the facial region, leading to swelling and obstruction of the follicular opening.
    • Buttock folliculitis
      • a common problem in both men and women
      • may be a form or localised acne
      • can be an acute condition with painful pustules requiring oral antibiotics
      • can also be chronic and require topical maintenance products to manage the condition.
    • Drug-induced folliculitis
      • presents as uniform red spots and pustules
      • more common in people prone to acne
      • occurs within two weeks of taking certain medications such as oral corticosteroids, androgenic hormones, epidermal growth factor receptor inhibitors, lithium and some other anticonvulsants
    • Pseudofolliculitis barbae
      • a type of chronic inflammation seen in the beard area of men who shave
      • mostly commonly affects men with darker skin types and tightly curled hair.
      • as the cut hair grows, the curliness leads to the sharp point digging into the skin causing a mechanical inflammation.
    • Irritant folliculitis
      • occurs on the lower legs of women who shave, wax, pluck or use electrolysis for hair removal.
    • Eosinophilic folliculitis
      • an itchy bumpy or pustular rash that most commonly affects the head and neck but other body sites may also be involved
      • unknown cause
      • in some cases may be related to immune suppression, either due to medications or medical conditions such as malignancy or HIV. Rarely, it occurs in infants

Reference:

1. Gunatheesan S. Folliculitis. www.dermcoll.edu.au/atoz/ folliculitis/ (accessed 10/3/2021).
2. Zacherle BJ et al.Hot tub folliculitis: a clinical syndrome. Western Journal of Medicine 1982;137(3):191-4.
3. Boni R et al.Treatment of gram-negative folliculitis in patients with acne. American Journal of Clinical Dermatology 2003;4(4):273-6.