Folliculitis

Basics

Description

  • Common skin condition involving inflammation of the hair follicle
  • Most frequent symptom is pruritus.
  • Painless or tender pustules, vesicles, or pink/red papulopustules up to 5 mm in size
  • Most commonly infectious in etiology:
    • Staphylococcus aureus bacteria
    • Pseudomonas aeruginosa infects areas of the body exposed to poorly sanitized hot tubs, pools, or contaminated water.
    • Fungal (dermatophytic, Pityrosporum, Candida)
    • Viral (VZV, herpes simplex virus [HSV])
    • Parasitic (Demodex mites, schistosomes)
  • Noninfectious types
    • Acneiform folliculitis
    • Actinic superficial folliculitis
    • Acne vulgaris
    • Keloidal folliculitis
    • Folliculitis decalvans
    • Perioral dermatitis
    • Fox-Fordyce disease
    • Pruritus folliculitis of pregnancy
    • Toxic erythema of the newborn
    • Eosinophilic folliculitis (seen in HIV positive/immunocompromised)
    • Follicular mucinosis
  • Skin disorders that may produce a follicular eruption:
    • Pseudofolliculitis barbae: similar in appearance; occurs after shaving; commonly known as razor bumps, occurs more frequently in black men
    • Atopic dermatitis
    • Follicular psoriasis
    • Rosacea

Epidemiology

Affects persons of all ages, gender, and race; those who shave or have chronic conditions such as diabetes or those who are immunocompromised are at increased risk.

Incidence
Superficial folliculitis is most commonly a self-limited condition; therefore, the exact incidence is not known.

Prevalence
Folliculitis is a relatively common skin condition; prevalence rate in the United States is 8 per 1,000.

Etiology and Pathophysiology

Predisposing factors to folliculitis

  • Chronic staphylococcal carrier
  • Diabetes mellitus
  • Malnutrition
  • Pruritic skin disease (e.g., scabies, eczema)
  • Exposure to poorly chlorinated swimming pools/hot tubs
  • Occlusive corticosteroid use (for multiple hours)
  • Bacteria
    • Most frequently due to S. aureus (increasing number of methicillin-resistant S. aureus [MRSA] cases)
    • Also due to Streptococcus species, Pseudomonas (following exposure to water contaminated with the species), or Proteus
    • May progress to furuncle and carbuncle
  • Fungal
    • Dermatophytic (tinea capitis, tinea corporis, tinea pedis)
    • Pityrosporum (Pityrosporum orbiculare) commonly affecting teenagers and men, predominantly on upper chest and back
  • Viral
    • HSV
    • Molluscum contagiosum
  • Parasitic
    • Demodex mites (commonly Demodex folliculorum), common around nasolabial area
    • Schistosomes (swimmer’s itch)
  • Acneiform type commonly drug induced (systemic and topical corticosteroids, lithium, isoniazid, rifampin), EGFR inhibitors
  • Severe vitamin C deficiency
  • Actinic superficial type occurs within 24 to 48 hours of exposure to the sun, resulting in multiple follicular pustules on the shoulders, trunk, and arms.
  • Acne vulgaris
  • Keloidal folliculitis is a chronic condition affecting mostly black patients; involves the neck and occipital scalp, resulting in hypertrophic scars and hair loss; usually consequence of uncontrolled folliculitis barbae
  • Folliculitis decalvans is a chronic folliculitis that leads to progressive scarring and alopecia of the scalp.
  • Rosacea consists of papules, pustules, and/or telangiectasias of the face; individuals are genetically predisposed; can be confused with folliculitis
  • Fox-Fordyce disease affects the skin containing apocrine sweat glands (i.e., axillae), resulting in follicular papules.
  • Eosinophilic pustular folliculitis has three variants: classic (Ofuji disease), associated with HIV infection, and infantile.
  • Toxic erythema of the newborn is a self-limiting pustular eruption usually appearing during the first 3 to 4 days of life and subsequently fading in the following 2 weeks.
  • Malassezia infections

Genetics
No known genetic predisposition

Risk Factors

  • Hair removal (shaving, plucking, waxing, epilating agents)
  • Other pruritic skin conditions: eczema, scabies
  • Occlusive dressing or clothing
  • Sweating
  • Personal carrier or contact with MRSA-infected persons
  • Diabetes mellitus
  • Immunosuppression (medications, chemotherapy, HIV)
  • Use of hot tubs or saunas
  • Use of EGFR inhibitors
  • Chronic antibiotic use (gram-negative folliculitis)
  • Tattoo recipient

General Prevention

  • Good hygiene practices
    • Wash hands frequently with antimicrobial soap.
    • Wash towels, clothes, and linens frequently with hot water to avoid reinfection.
  • Good hair removal practices
    • Exfoliate beforehand.
    • Use witch hazel, alcohol, or Tend Skin afterward.
    • Shave in direction of hair growth; use shaving gel and moisturizer.
    • Decrease frequency of shaving.
    • Use clippers primarily or single-blade razors if straight shaving is desired.

Commonly Associated Conditions

Impetigo, scabies, acne, follicular psoriasis, eczema, xerosis, Staphylococcus/MRSA colonization

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