Folliculitis, in its broadest sense, may be defined as a superficial or deep infection or inflammation of the hair follicles. It has multiple causes: various infections, physical or chemical irritation, occlusive dressings or clothing, and the use of topical or systemic steroids.
Hereditary forms of folliculitis,
such as follicular eczema (generally classified under "atopic dermatitis"), and the deeper forms of inflammatory folliculitis that involve the entire follicular structure, such as folliculitis decalvans, occur most commonly in blacks. Folliculitis may also be seen as a secondary infection in conditions such as eczema, scabies, and excoriated insect bites. It is more commonly found in patients who are diabetic, obese, or immunocompromised.
Coagulates-positive Staphylococcus aureus is the responsible pathogenic bacterium in most cases of infectious folliculitis. Folliculitis may evolve into afuruncle (boil), which is a deep infection; a carbuncle refers to an aggregation of furuncles. The discussion in this article will be limited to the superficial forms of folliculitis.
PHYSICAL FINDINGS
A pustule or papule with a central hair is the primary lesion in folliculitis. Secondary lesions evolve from ruptured pustules and may consist of erosions, crusts, and darkly pigmented macules. The central hair shaft may not always be visible. Follicular lesions tend to exist in a gridlike pattern on hair-bearing areas of the body.
CAUSES AND
PRECIPITATING
FACTORS
Patients with conditions that reduce host resistance, such as diabetes or human immunodeficiency virus infection, are more likely to develop an infectious bacterial, viral, or fungal folliculitis. Folliculitis is more common in carriers of aureus, particularly nasal carriers. Infectious and inflammatory folliculitis may be seen in areas of skin subjected to:
-Repeated trauma (such as waxing, plucking, and shaving).
-Friction.
- Restrictive clothing, such as tight jeans.
- Excessive sweating.
Folliculitis is more commonly seen in the obese. Inflammatory folliculitis (follicular eczema) with episodic bacterial superinfection is more likely to occur in patients with atopic dermatitis.
STAPHYLOCOCCAL FOLLICULITIS
S aureus folliculitis is the most common type. It may occur in crops of pustules and/or papules on the scalp, thighs, legs, axillae, and inguinal areas. Folliculitis involving an eyelash is called a hordeolum, or sty. Similarly, folliculitis may affect a single nasal hair follicle and produce a tender erythematous papule or pustule within the nasal mucosa or near the tip of the nose.
OTHER FORMS OF FOLLICULITIS
Folliculitis is not always caused by S aureus. Other forms of folliculitis may be caused by organisms acquired in hot tubs or by irritation, friction, chemicals, steroids, or fungi. In addition, therapeutically recalcitrant folliculidities, such as the herpes simplex infections or eosinophilic pustular folliculitis, may be seen in patients with acquired immunodeficiency syndrome (AIDS).
HOT TUB FOLLICULITIS Pseudomonas folliculitis, which may be acquired from communal hot tubs, is caused by Pseudomonas aeruginosa infection. Although they have increased the incidence of folliculitis, hot tubs are often overlooked as a cause. Jacuzzis, therapeutic whirlpools ("whirlpool folliculitis"), public swimming pools, and the use of loofah sponges may also be a source of Pseudomonas infection. Pseudomonas folliculitis has recently been found to occur under diving suits and after wax depilation. Lesions of hot tub folliculitis consist of intensely pruritic or tender follicular papules and/or pustules that are most often found on the trunk (the area covered by a bathing suit). They occur one to three days after bathing in a hot tub, whirlpool, or public swimming pool.
Nonbacterial, or sterile, folliculitis can arise from physical or chemical irritation. Such irritants include leg waxing, leg shaving, axillary shaving, and hair plucking. Chemical depilatories, electrolysis, occlusive dressings, and excessive sweating can also contribute to this problem, as can wear tight jeans. Nonbacterial folliculitis may also be related to working conditions, such as the use of greases or oils, and to the application of various cosmetics. Bacteria, such as S aureus, are not infrequent secondary invaders