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For further information, see CMDT Part 6-29: Folliculitis (Including Sycosis)

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


  • Clinical

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



Table 6–2.Useful topical dermatologic therapeutic agents.1

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