Folliculitis is an inflammatory condition of the hair follicle that is caused by infection, physical injury, or chemical irritation.
The most common type of folliculitis is infectious. This is usually secondary to Staphylococcus aureus, which is treated with topical or oral antibiotics.
Staphylococcal folliculitis is particularly prevalent in the African American human immunodeficiency virus (HIV)-positive population.
The noninfectious folliculitides are induced by drugs or chemicals, or they are activated mechanically.
Eosinophilic folliculitis is a rare sterile folliculitis encompassing the classic Ofuji disease, HIV-associated eosinophilic folliculitis, and eosinophilic pustular folliculitis of infancy.
Certain perifolliculocentric inflammatory disorders, such as pseudofolliculitis barbae, acne keloidalis nuchae, and perifolliculitis capitis abscedens et suffodiens, although not true folliculitides, can often mimic folliculitis and are seen more often in African Americans.
SYNONYMS FOR FOLLICULITIS
Pseudofolliculitis barbae (PFB)
Tufted hair folliculitis
Perifolliculitis capitis abscedens et suffodiens
Disseminated and recurrent infundibular folliculitis
Folliculitis is a disease of the hair follicle that is usually caused by an infection. However, it can also be induced by irritation, chemical agents, medications, physical injury, or other factors that cause disruption and obstruction of the hair follicles and associated pilosebaceous units. The classification of folliculitis is complex, but this class of diseases is generally divided into infectious [Table 41-1] and noninfectious folliculitis and perifolliculitis [Table 41-2]. Perifolliculitis refers to inflammation in the perifollicular tissue and occasionally the adjacent reticular dermis. In addition to the classification of folliculitis according to its causative organism, this condition can also be designated as superficial or deep. Superficial folliculitis is when the upper portion of the hair follicle, the follicular infundibulum, is involved. Deep folliculitis is, when the inflammation extends into the isthmus and deeper portions of the follicle. In superficial folliculitis, the follicular inflammation is confined, leading to the formation of the characteristic clustered, 1- to 4-mm erythematous papule pustules that typically heal without scarring. This type of folliculitis is usually seen in areas with terminal hair strands. Deep folliculitis is characterized by large, tender erythematous papules or nodules that can scar. The purulent material can extend into the subcutaneous tissue forming a large, deep mass or furuncle. Several infected follicles can coalesce to form a large mass or carbuncle.
TABLE 41-1Common nonstaphylococcal infectious folliculitides ||Download (.pdf) TABLE 41-1 Common nonstaphylococcal infectious folliculitides
|Type ||Clinical features |
|Bacterial folliculitis |
|Pseudomonas aeruginosa folliculitis ||Develops after exposure to contaminated water in hot tubs, whirlpools, swimming pools, water slides, and bathtubs |
|Gram-negative folliculitis ||Occurs at site of acne vulgaris, often on the face after long-term antibiotic therapy |
|Fungal folliculitis |
|Tinea barbae ||Due to Trichophyton mentagrophytes var. mentagrophytes or T. verrucosum; it is classically found in male farm workers |
|Majocchi granuloma ||This is usually due to Trichophyton rubrum, and characteristically ...|