Superficial Folliculitis

Aka: Superficial Folliculitis, Folliculitis, Staphylococcal Folliculitis

1. Pathophysiology
   1. Usually caused by Bacterial Infection
   2. Superficial inflammation of Hair Follicle
      1. Only upper Hair Follicle involved
      2. Contrast with Deep Folliculitis
2. Risk Factors
   1. Local Trauma
      1. Abrasion
      2. Surgical wounds or draining abscess
      3. Shaving
         1. Aggravates Staphylococcus aureus Folliculitis
   2. Exposure to Occlusive Dressing
      1. Tar
      2. Adhesive plaster
      3. Plastic Occlusive Dressings
3. Causes
   1. See Folliculitis
   2. Staphylococcal Folliculitis (most common)
      1. Affects beard area (Folliculitis barbae)
      2. Also affects axillae and legs
      3. Aggravated by shaving
   3. Pseudomonas Folliculitis (Hot Tub Folliculitis)
   4. Pseudofolliculitis Barbae
   5. Eosinophilic Folliculitis (HIV)
   6. Superficial Fungal Infection
      1. Malassezia Folliculitis
      2. Dermatophyte Folliculitis
      3. Candida Folliculitis
   7. Viral Folliculitis
      1. Herpetic Folliculitis
      2. Molluscum Folliculitis
   8. Drug-Induced-Folliculitis
      1. Steroid Folliculitis (corticoseroids)
      2. Phenytoin
      3. Lithium
      4. Isoniazid
      5. Cyclosporine
      6. Epidermal Growth Factor Receptor Inhibitors or EGFR Inhibitors (e.g. Erbitux, Vectibix, Tarceva, Iressa, Tykerb)
4. Symptoms
   1. Non-tender or minimally tender
   2. Variably pruritic
5. Signs
   1. Characteristics
      1. Pustule confined to Hair Follicle
      2. Hair Shaft may be seen at center of lesion
      3. Yellow or gray coloration with erythema
   2. Distribution: Any skin bearing hair
      1. Head and neck
      2. Trunk
      3. Buttocks
      4. Extremities
   3. Absent features
      1. No associated fever or systemic symptoms
6. Differential Diagnosis
   1. Acne Vulgaris
   2. Acne Keloidalis Nuchae
   3. Papulopustular Rosacea
   4. Keratosis Pilaris (younger patients)
   5. Hidradenitis Suppurativa
   6. Cutaneous Candidiasis (Candida albicans)
      1. Seen in febrile hospitalized patients
   7. Beard area Folliculitis
      1. See Beard Dermatitis
   8. Trunk Folliculitis
      1. Tinea Corporis (Ringworm)
      2. Pustular Miliaria
         1. Not perifollicular
         2. Occurs in hot, humid weather
7. Labs (As Indicated)
   1. Pustule Gram Stain and Culture
   2. KOH Preparation
   3. Fungal Culture
   4. Skin Biopsy
   5. Nasal MRSA Swab
8. Management
   1. General
      1. Eliminate provocative agents (tar, Mineral Oil)
      2. Keep affected areas clean and dry
      3. Avoid occlusive clothing and excessive sweating
      4. Consider warm, wet Burow's Solution
      5. Consider Topical Corticosteroids for significant associated inflammation
   2. Approach to infection management
      1. Staphylococcal Folliculitis is most common, but is not the only Folliculitis cause (see causes above)
      2. Consider Pseudomonas Folliculitis (Hot Tub Folliculitis)
      3. Consider Gram Negative Folliculitis
      4. Consider fungal Folliculitis (dermatophyte Folliculitis, candida Folliculitis)
   3. Staphylococcal Folliculitis
      1. Topical Antibiotics
         1. Apply Mupirocin ointment three times daily to affected areas for 7 to 10 days or
         2. Topical Clindamycin (Cleocin-T) twice daily for 7 to 10 days
      2. Systemic Antibiotics (refractory to topical agents)
         1. Avoid Macrolides due to increased resistance
         2. Dicloxacillin 250 to 500 mg orally four times daily for 7 to 10 days or
         3. Cephalexin (Keflex) 250 to 500 mg orally four times daily for 7 to 10 days or
         4. Cefadroxil (Duricef) 500 mg orally twice daily for 7 to 10 days or
         5. Doxycycline 100 mg orally twice daily for 7 to 10 days (MRSA coverage) or
         6. Trimethoprim-Sulfamethoxazole (Septra, Bactrim) orally twice daily for 7 to 10 days (MRSA coverage)
      3. Prevention (Suppression of infection)
         1. Daily washing with antimicrobial skin cleanser (e.g. Benzoyl Peroxide)
         2. Topical Clindamycin (Cleocin T) after shaving
         3. Mupirocin (Bactroban) in nostrils
9. Course
   1. Heals without scarring
10. References
    1. Jackson in Rosen (2022) UpToDate, Accessed online 8/8/2022
    2. Fitzpatrick (1992) Color Atlas Dermatology
    3. Habif (1996) Dermatology, p. 248-51
    4. Stulberg (2002) Am Fam Physician 66(1):119-24 [PubMed]