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