|A single spot of folliculitis|
|Symptoms||Tender small pustule or red bump|
|Types||Bacterial folliculitis, hot tub folliculitis, fungal folliculitis, malassezia folliculitis|
|Risk factors||Diabetes, obesity, antibiotic use, poor immune function, shaving|
|Diagnostic method||Based on symptoms and examination|
|Differential diagnosis||Acne, papulopustular rosacea, pseudofolliculitis barbae, keratosis pilaris|
|Treatment||Depends on the cause, often conservative|
Folliculitis is infection or inflammation of one or more hair follicles resulting in a small pustule or red bump. These are generally tender. The condition may occur anywhere on hair covered skin. Complications include cellulitis or abscess.
It most commonly occurs due to a bacterial infection though less commonly may result from a fungal, viral, or noninfectious cause. Risk factors include diabetes, obesity, antibiotic use, poor immune function, shaving and certain medications like lithium. Diagnosis is generally based on symptoms and examination.
Treatment depends on the underlying cause but is often conservative. When due to Staph. aureus, while a few lesions may resolve on their own, larger numbers of lesions may be treated with antibiotic cream or pills. When due to hot tube use, the outbreak will generally resolve without treatment within 10 days. The condition is common.
Signs and symptoms
- rash (reddened skin area)
- itching skin
- pimples or pustules located around a hair or follicle; may be confused with chicken pox
- spreading from leg to arm to body through improper treatment with antibiotics
Folliculitis starts with the introduction of a skin pathogen to a hair follicle. Hair follicles can also be damaged by friction from clothing, an insect bite, blockage of the follicle, shaving, or braids that are too tight and too close to the scalp. The damaged follicles are then infected by Staphylococcus. Folliculitis can affect people of all ages.
Iron deficiency anemia is sometimes associated with chronic cases.
- Staphylococcus aureus folliculitis.
- Hot-tub folliculitis is caused by the bacterium Pseudomonas aeruginosa. The folliculitis usually occurs after sitting in a hot tub that was not properly cleaned before use. Symptoms are found around the body parts that sit in the hot tub: the legs, hips, chest, buttocks, and surrounding areas. Symptoms are amplified around regions that were covered by wet clothing, such as bathing suits.
- Sycosis vulgaris, Sycosis barbae or Barber's itch is a staphylococcus infection of the hair follicles in the bearded area of the face, usually the upper lip. Shaving aggravates the condition.
- Gram-negative folliculitis may appear after prolonged acne treatment with antibiotics.
- Tinea barbae is similar to barber's itch, but the infection is caused by the fungus T. rubrum.
- Malassezia folliculitis, formerly known as Pityrosporum folliculitis, is caused by yeasts (fungi) of the genus Malassezia 
- Herpetic folliculitis rarer, but may occur when herpes simplex virus infection spreads to nearby hair follicles appearing in groups or clusters, mostly around the mouth.
- Pseudofolliculitis barbae is a disorder occurring when hair curves back into the skin and causes inflammation.
- Eosinophilic folliculitis may appear in persons with impaired immune systems.
- Folliculitis decalvans or tufted folliculitis usually affects the scalp. Several hairs arise from the same hair follicle. Scarring and permanent hair loss may follow. The cause is unknown.
- Reaction to Demodex mite infestation may occasionally be misdiagnosed as folliculitis.
- Folliculitis keloidalis scarring on the nape of the neck. Most common among males with curly hair.
- Oil folliculitis is inflammation of hair follicles due to exposure to various oils and typically occurs on forearms or thighs. It is common in refinery workers, road workers, mechanics, and sheep shearers. Even makeup may cause it.
- Malignancy may also be represented by recalcitrant cases.
Most simple cases will resolve on their own but first line treatments are typically topical medications.
- Topical antiseptic treatment is adequate for most cases
- Topical antibiotics, such as mupirocin or Neomycin/polymyxin B/bacitracin ointment may be prescribed. Oral antibiotics may also be used.
- Some patients may benefit from systemic narrow-spectrum penicillinase-resistant penicillins (such as dicloxacillin in US, or flucloxacillin in UK)
- Fungal folliculitis may require an oral antifungal such as Fluconazole. Topical antifungals such as Econazole Nitrate may also be effective.
Folliculitis may recur even after symptoms have gone away.
- Winters, RD; Mitchell, M (January 2020). "Folliculitis". PMID 31613534. Cite journal requires
- "Folliculitis | DermNet NZ". dermnetnz.org. Retrieved 14 November 2020.
- "NHS Direct".
- MedlinePlus Encyclopedia: Hot tub folliculitis
- "Severe Acne: 4 types". American Academy of Dermatology. Archived from the original on February 9, 2011. Retrieved December 15, 2010.
- Folliculitis, follicular mucinosis, and papular mucinosis as a presentation of chronic myelomonocytic leukemia. Rashid R, Hymes S. Dermatol Online J. 2009 May 15;15(5):16.