REFERENSI : Journal (Clinical Key)

Abstract

Facial bacterial infections are most commonly caused by infections of hair follicles. Wherever pilosebaceous units are found, folliculitis can occur, and the most common bacterial cause of folliculitis is Staphylococcus aureus. We review different forms of facial folliculitis, distinguishing bacterial forms from other infectious and noninfectious mimickers. We distinguish folliculitis from pseudofolliculitis and perifolliculitis. Clinical features, etiology, pathology, and management options are discussed.

Introduction

Folliculitis properly refers to inflammation of the hair follicle. This may occur from a number of etiologies, infectious and noninfectious. Infectious folliculitis may be bacterial or nonbacterial (viral, fungal, parasitic). Infectious folliculitis may be superficial or deep, with significant differences in clinical presentation and treatment. When noninfectious, folliculitis may occur secondary to follicular trauma or occlusion.

In general, superficial folliculitis is more easily treated than deep folliculitis, and infectious folliculitis is generally more amenable to treatment than folliculitis of noninfectious causes.

Clinical features

Facial bacterial skin infections are common, and the most common infection of the face is bacterial folliculitis caused by Staphylococcus aureus. Facial bacterial folliculitis manifests as clusters of multiple small, raised, pruritic, erythematous papules usually less than 5 mm in diameter. Pustules may be present. The onset is usually acute. 1 Folliculitis may be superficial or deep, depending on which part of the hair follicle is affected.

Superficial folliculitis typically consists of multiple small papules and pustules on an erythematous base, each papule or pustule pierced by a central hair. These superficial lesions usually heal without scarring. Deep folliculitis commonly manifests as plaques and nodules. Pustules, when present, usually overlie erythema and induration. Commonly, deep folliculitis is painful and heals with scarring. 2 Sometimes a patterned area of folliculitis arises in areas that were shaved or occluded. Any hair-bearing site can be affected, but the sites most often involved are the face and scalp. Superficial infections can evolve into deep infections.

A common variant of superficial folliculitis is impetigo of Bockhart ( Figure   1 ). Poor hygiene and occlusion of the skin have been implicated as promoting factors, with the causative bacterial culprit being S aureus. Unlike streptococcal infections, which spread as they dissect through collagen, follicular infections secondary to S aureus tend to remain relatively localized as pustules rather than vesiculobullae. Clinically, one encounters a domed yellow pustule, sometimes with a narrow red areola. Using a hand lens, one may identify a small hair piercing each pustule. The pustules develop in crops and heal in 7 to 10 days with or without treatment, but they may also become chronic. In older children and adults, the infection may extend more

deeply as furuncles, and, in some cases, chronic Bockhart's impetigo may merge imperceptibly with folliculitis decalvans and related processes. 3

Fig. 1

Impetigo.

Among acne patients, the causative organisms for superficial facial folliculitis tend to be gram negative. Approximately 4% of patients with acne vulgaris treated with systemic antibiotics—most commonly tetracycline—develop the sudden onset of a gram-negative bacterial superficial folliculitis. This type of folliculitis develops when normal skin flora (eg, S epidermidis) are replaced or displaced by gram-negative organisms ( Enterobacter, Klebsiella, Escherichia, Serratia, and Proteus spp). The lesions usually arise in the perinasal region as multiple small pustules that spread to the cheeks and chin.

When involvement of the follicle is more extensive and deep, a follicular-centered dermal furuncle or boil results. When the deep follicular infection involves the beard areas or the chin, it is known as folliculitis barbae vulgaris, a condition that tends to be chronic. The erythematous papules and pustules that form around the coarse hairs in the beard range from asymptomatic to painful and tender. 7 Commonly the causative organism is a species of Staphylococcus or Propionibacter.

Nasal furunculosis is a deep infection of the hair follicle within the nasal vestibule. The tip of the nose becomes red and very painful. A nodule may be palpated or even visualized in the nasal vestibule ( Figure   2 ). The likely causative bacteria is S aureus.

Fig. 2

Pathology

Acute bacterial folliculitis usually shows neutrophils infiltrating around a hair follicle. In superficial folliculitis, the neutrophils are confined to the infundibulum; in deep folliculitis, neutrophils infiltrate the deeper portion of the follicle and surrounding dermis. 8 Older lesions show chronic granulomatous inflammation with giant cells containing keratin and fragmented hair. 9 Although suppurative folliculitiis often heals without clinical residue, some longstanding conditions may progress from suppuration to the formation of granulomas or fibrosis with evident clinical scarring.

Staphylococcal folliculitis commonly shows a subcorneal abscess with abscess of the follicular infundibulum and infection of the more superficial aspects of the surrounding dermis. Factors implicated in increasing the risk of staphylococcal folliculitis include immunosuppression (eg, HIV) 10 and reduction in white blood cell production (eg, isotretinoin therapy). 11 Similarly, other immunosuppressive medications (eg, corticosteroids) or immunosuppressive conditions (eg, diabetes), increase the risk of folliculitis.

Staphylococci are responsible for many cases of facial folliculitis, but in some forms the role of bacteria remains unclear. Folliculitis barbae, for example, is a deep folliculitis occurring in beard areas. S aureus can often be isolated from the noses of these patients 12 ; however, Staphylococcus usually penetrates no deeper than the follicular ostia, and so this is considered a noninfectious form of folliculitis (see below).

Differential diagnosis

Bacterial folliculitis must be differentiated from other infectious causes of facial folliculitis: Viruses (eg, herpes simplex, varicella-zoster, molluscum contagiosum), fungi (eg, Candida, Pityrosporum), and parasites (eg, Demodex folliculorum).

Noninfectious folliculitis is most commonly caused by follicular trauma or follicular occlusion. Follicles may be traumatized during shaving or during hair removal with tweezers. Folliculitis secondary to follicular occlusion is seen with the use of adhesive dressings, with topically

applied oils (suntan oils, hair oils, and bath oils), and with occupational exposure to solvents and tars. 13 In these cases, the lesions commonly present as small, follicular papules or pinhead pustules over the face, neck, arms, thighs, or buttocks. They are rarely painful. The pustule is often sterile.

Acne vulgaris is also a kind of noninfectious folliculitis induced by follicular occlusion. Abnormal keratinization results in the formation of a keratin plug, which obstructs outflow of sebum from the follicle. Sebum fills the follicle, providing abundant substrate for Propionobacter acnes to metabolize sebum into proinflammatory free fatty acids.

Eosinophilic folliculitis is noninfectious and of unclear etiology. Clinically, eosinphilic folliculitis manifests as intensely pruritic pustules. Among Japanese men, eosinophilic pustular folliculitis (Ofuji disease) arises at an average age of 30 years. The lesions initially begin as discrete papules and pustules on the face, back, and extensor surfaces of the arms. These lesions eventually coalesce to form circinate plaques composed of a peripheral rim of pustules and central clearing within the plaque. The lesions reappear cyclically and spontaneously resolve in 7 to 10 days. Peripheral eosinophilia is often present. 14

In the eosinophilic folliculitis of AIDS or other immunosuppression, the pruritic papules typically appear over the face, scalp, and upper trunk of adult men with a CD4 + count of less than 300 cells/μL. 15

Pseudofolliculitis barbae is clearly associated with shaving and tightly kinked (curled) hair. The patient complains of minor tenderness or pain, pruritus, and cosmetic embarrassment from erythematous papules or pustules over the beard area—most commonly over the submandibular neck in men who shave. The papules and pustules may develop into persistent hypertrophic, keloidal-appearing scars.

Pseudofolliculitis barbae develops when tightly kinked hair is closely shaved and curves back into the skin, penetrating to the dermis and inducing a foreign body reaction ( Figure   3 ). 16

Properly, this condition is a perifolliculitis, rather than a folliculitis, because the hair shaft reenters the skin adjacent to its exit point (the follicle). Unsheathed hair (keratin), highly immunogenic to the dermis, incites inflammation, causing a chronic foreign body granulomatous reaction with scarring. When pseudofolliculitis barbae is pustular, there is commonly a secondary superinfection with S epidermidis. 16

Fig. 3

Tightly kinked hairs also play a role in the pathogenesis of folliculitis keloidalis nuchae, in which small follicular papules or pustules develop on the nape of the neck and often extend to the posterior scalp. These lesions give rise to hard, pruritic papules, which may coalesce into large, firm, keloidal-appearing plaques and nodules ( Fig. 3 Fig. 4 ). Histologically, they resemble scar tissue, rather than true keloids. 17

Fig. 4

Treatment

When managing folliculitis, we consider etiology, severity, and anatomic distribution. Many forms of folliculitis respond to the topical application of warm normal saline compresses (1 teaspoon of table salt in 2 cups of tap water), followed by application of bacitracin or erythromycin ointment and sterile absorbent gauze dressings. 18 For mild cases caused by S aureus, a 7- to-10-day course of oral erythromycin may be used (250-500 mg qid for adults and 30-50 mg/kg/day in equally divided doses every 6 hours for children). When the infection recurs, the search for a bacterial reservoir (eg, nose, teeth, tonsils) may be important. Triple antibiotic ointment (bacitracin/polysporin/neomycin) has been reported to be effective in preventing streptococcal pyoderma in children at increased risk for such infections. 19 The topical antibiotic mupirocin (Bactroban) has been reported to reduce nasal carriage of S aureus and may aid in the treatment of chronic S aureus folliculitis.

Recurrent deep folliculitis (boils or carbuncles), typically caused by Staphylococcus, is more difficult to treat. For lesions that are conical with a pustular head, initial treatment consists of incision and drainage. After local application of heat, a small (2-4 mm) incision (to minimize scarring) is made with a number 11 blade. Boils or carbuncles may require several months of treatment with oral antibiotics. Dicloxacillin and a cephalosporin are first-line therapies, given the growing prevalence of resistance to penicillin. With methicillin-resistant organisms more common, clindamycin, trimethoprim-sulfamethoxazole, tetracyclines (minocycline, doxycycline), erythromycin, or linezolid may be used.

For gram-negative folliculitis complicating acne treatment, after discontinuing the implicated antibiotic, administer ampicillin or trimethoprim-sulfamethoxazole for an additional 10 to 14 days after the lesions have resolved. 4

In most cases of pseudofolliculitis barbae, growing a beard is curative. When the patient insists on shaving closely, topical clindamycin lotion helps reduce secondary infections. Topical retinoic acid or topical antibiotic with steroid helps control the condition. 20 Surgical depilation is an option when other therapy has failed. 21

Folliculitis barbae requires a basic approach of antibacterial soap, local warm saline compresses, and topical antibiotics, whereas more extensive cases may require systemic antibiotics.

For folliculitis keloidalis nuchae, topical clindamycin combined with fluocinolone acetonide gel is useful. Radiotherapy has not produced impressive results for the earlier inflammatory stage or the late fibrous plaque stage of this disorder; however, intralesional corticosteroids or surgical removal of subfollicular diseased tissue may be helpful in advanced cases

REFERENSI : BOLOGNIA

Pathology

A moderately intense follicular infiltrate of lymphocytes, neutrophils and macrophages is seen, with extension of the neutrophils into the follicular epithelium and follicular canal aggregating variably to form an abscess. Late-stage changes include follicular rupture and a granulomatous response. Tissue Gram stain and stains for fungi may reveal pathogenic organisms.

Treatment

The treatment chosen depends upon the culture results (see Ch. 73). For culture-negative folliculitis, the treatments include topical benzoyl peroxide, topical antibiotics (e.g. clindamycin), and oral antibiotics (e.g. tetracycline or doxycycline), with the anti-inflammatory properties of these antibiotics perhaps playing a role. This should be combined with an attempt to reduce overhydration of the skin, occlusion and irritation[1].