Boils

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24th November 2017
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Overview

Folliculitis is a superficial inflammation of the hair follicle caused by injury, chemical irritation, or infection. Furuncles (abscess or boil) and carbuncles occur when folliculitis extends from the hair shaft to deeper tissues.

Epidemiology and Etiology

Age of onset
Children, adolescents, and young adults.

Sex
More common in boys.

Etiology
Most commonly MSSA. Community acquired MRSA becoming more common. Outbreaks of P. aeruginosa infections are associated with inadequately chlorinated pools, hot tubs, etc.

Predisposing factors

  • Chronic S. aureus carrier state (nares, axillae, perineum, vagina).
  • Diabetes Mellitus.
  • Obesity.
  • Poor hygiene.
  • Immunocompromised.
  • Hyper-IgE syndrome (Job’s syndrome).
  • Corticosteroid use.

Pathogenesis

Folliculitis, furuncles, and carbuncles represent a continuum of severity of S. aureus infection. Portal of entry: Hair follicle, break in the integrity of skin. MRSA infections often have high morbidity due to delay in administration of effective antibiotic. Control or eradication of carrier state treats / prevents folliculitis, furuncle, and carbuncle formation.

Infectious causes:

  • S. aureus (most common).
  • Streptococcus species.
  • Mixed bacteria infection.

Risk factors of Folliculitis

Local Trauma

  • Abrasions.
  • Surgical wounds or draining abscess.
  • Shaving.

 

Aggravates S. Aureus Folliculitis

  • Exposure to occlusive dressing.
  • Tar.
  • Adhesive plaster.
  • Plastic occlusive dressing.

Furuncles

Usually occur in areas of friction or perspiration. Lesion is usually a firm, tender, red nodule that becomes more painful and may drain pus.

  • Known as abscess or boils.
  • Usually start as folliculitis.
  • Deep folliculitis – spread to deeper tissue

 

Walled off nodule of purulent infection:

  • Painful.
  • Firm or fluctuant.
  • Fever is uncommon.
  • Can be at any site.
  • Most often in areas of friction.

Carbuncles

  • Broad, swollen, erythematous, deep, and painful masses, usually on the back of the neck.
  • Patient with diabetes especially susceptible.
  • Commonly associated with constitutional symptoms such as fever and chills.
  • Bacteremia and spread are a risk.
  • Uncommon in children

 

Carbuncle involves a coalition of furuncles:

  • Deeper, more extensive involvement
  • Require greater degree of debridement

Management

  • Antimicrobial treatment usually not necessary for smaller boils.
  • Warm saline compresses to promote drainage.
  • Incision and drainage may be required, especially for carbuncles.
  • Topical antibiotics.
  • Mupirocin (Bactroban) cream or ointment.
  • Fucidin cream or ointment.
  • Erythromycin 2% solution.
  • Clindamycin Solution.
  • To be applied two to three times a day for 7 to 10 days.
  • Only applicable for smaller boils.
  • Systemic antibiotics.
  • Cloxacillin (covers methicillin-sensitive S. aureus [MSSA] and S. pyogenes):
    – Adults: 250–500 mg orally every 6 hours.
    – Pediatrics: 25–50 mg/kg orally divided into four doses.
  • Cephalexin (covers MSSA and S. pyogenes)
    – Adults: 250–500 mg orally every 6 hours.
    – Pediatrics: 25–50 mg/kg orally divided into four doses.
  • Clindamycin (covers MSSA, some CA-MRSA, and S. pyogenes)
    – Adults: 300–600 mg orally every 6–8 hours.
    – Pediatrics: 10–30 mg/kg/day orally divided into three or four doses.
    – Is an oral option for CA-MRSA, but is cross-resistant with erythromycin.
  • Antimicrobial treatment should be for 7–10 days.

Surgery

Incision and drainage are often adequate for treatment of abcesses, furuncles or carbuncles.

Recurrent Furunculosis

Usually related to persistent s. aureus in the nares, perineum, and body folds.

Topical Therapy 

Shower with povidone iodine soap. Apply mupirocin ointment daily to the inside of nares and other sites of s.aureus carriage.

Systemic Therapy

Appropriate antibiotic treatment is continued until all lesions have resolved. Secondary prophylaxis may be given once a day for many months.

Carrier State

Rifampicin: 600mg PO for 7 to 10 days for eradication of carrier state.

References

  • Stevens DL, Bisno AL, Chambers HF, et al. Prac­tice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin Infect Dis 2005;41:1371–406.
  • Liu C, Bayer A, Cosgrove E, et al. Clinical prac­tice guidelines by the Infectious Diseases Society of America for treatment of methicillin-resistant Staphylococcus aureus infections in adults and children. Clin Infect Dis 2011;52:1–38.
  • Bisno AL, Stevens DL. Streptococcal infections of skin and soft tissues. N Engl J Med 1996;334:240–5.
  • Tennvall GR, Apelqvist J, Eneroth M. Costs of deep foot infections in patients with diabetes mel­litus. Pharmacoeconomics 2000;18:225–38.
  • Fitzpatrick’s. Color Atlas and Synopsis of Clinical Dermatology 5th edition. McGraw Hill New York 2005. Pg 586 – 560.