Folliculitis

Key Features

Essentials of Diagnosis

• Itching and burning in hairy areas

• Pustules surrounding and including the hair follicle

General Considerations

• Frequently caused by staphylococcal infections

• May be more common in diabetic persons

• Gram-negative folliculitis

  • Klebsiella

  • Enterobacter

  • Escherichia coli

  • Proteus

• "Hot tub folliculitis"

  • Caused by Pseudomonas aeruginosa

• Nonbacterial folliculitis

  • May be caused by friction and oils

  • Occlusion, perspiration, and rubbing, such as that resulting from tight jeans and other heavy fabrics on the upper legs, may worsen

• Eosinophilic folliculitis

  • A form of sterile folliculitis

• Pseudofolliculitis

  • Caused by ingrowing of tightly curled hairs in the beard area

• Demodex folliculitis

  • Caused by the mite Demodex folliculorum

  • More common in immunosuppressed patients

Clinical Findings

Symptoms and Signs

• The symptoms range from slight burning and tenderness to intense itching

• The lesions consist of pustules of hair follicles

• Sycosis

  • Deep-seated, chronic, recalcitrant lesion on the head and neck

• Gram-negative folliculitis

  • May develop during antibiotic treatment of acne

  • May present as a flare of acne pustules or nodules

• "Hot tub folliculitis"

  • Characterized by pruritic or tender follicular or pustular lesions occurring within 1–4 days after bathing in a hot tub, whirlpool, or swimming pool

  • Systemic flu-like symptoms may be present

  • Rarely, systemic infections may result

• Nonbacterial folliculitis

  • May be caused by friction and oils

  • Occlusion, perspiration, and chronic rubbing (eg, from tight jeans or other heavy fabrics on the buttocks and thigh) can worsen this type of folliculitis

• Corticosteroid therapy-related folliculitis may be seen during topical or systemic corticosteroid therapy—so-called steroid acne

• Eosinophilic folliculitis

  • Consisting of urticarial papules with prominent eosinophilic infiltration

  • Common in patients with AIDS

• Pseudofolliculitis

  • Papules and pustules are located at the side of and not in follicles

• Malassezia (Pityrosporum) folliculitis

  • Presents as 1–2-mm pruritic pink papulopustules on the upper trunk, hairline, and arms

  • Tends to develop during periods of excessive sweating

  • Can also occur in immunosuppressed patients

• Demodex folliculitis

  • Presents as 1–2 mm papules and pustules on an erythematous base, often on the background of rosacea-like changes, in patients who have not responded to conventional treatment for rosacea

Differential Diagnosis

• Acne vulgaris

• Miliaria (heat rash)

• Impetigo

• Tinea

• Pseudofolliculitis barbae (ingrown beard hairs)

• Hidradenitis suppurativa

Diagnosis

• Clinical

• In demodex folliculitis, KOH from the pustules will demonstrate Demodex folliculorum mites

Treatment

Medications

• See Table 6–2