> Table of Contents > Furunculosis
Furunculosis
Zoltan Trizna, MD, PhD
image BASICS
DESCRIPTION
  • Acute bacterial abscess of a hair follicle (often Staphylococcus aureus)
  • System(s) affected: skin/exocrine
  • Synonym(s): boils
EPIDEMIOLOGY
Incidence
  • Predominant age
    • Adolescents and young adults
    • Clusters have been reported in teenagers living in crowded quarters, within families, or in high school athletes.
  • Predominant sex: male = female
Prevalence
Exact data are not available.
ETIOLOGY AND PATHOPHYSIOLOGY
  • Infection spreads away from hair follicle into surrounding dermis.
  • Pathogenic strain of S. aureus (usually); most cases in United States are now due to community-acquired methicillin-resistant S. aureus (CA-MRSA) whereas methicillin-sensitive S. aureus (MSSA) is most common elsewhere (1).
Genetics
Unknown
RISK FACTORS
  • Carriage of pathogenic strain of Staphylococcus sp. in nares, skin, axilla, and perineum
  • Rarely, polymorphonuclear leukocyte defect or hyperimmunoglobulin E-Staphylococcus sp. abscess syndrome
  • Diabetes mellitus, malnutrition, alcoholism, obesity, atopic dermatitis
  • Primary immunodeficiency disease and AIDS (common variable immunodeficiency, chronic granulomatous disease, Chediak-Higashi syndrome, C3 deficiency, C3 hypercatabolism, transient hypogammaglobulinemia of infancy, immunodeficiency with thymoma, Wiskott-Aldrich syndrome)
  • Secondary immunodeficiency (e.g., leukemia, leukopenia, neutropenia, therapeutic immunosuppression)
  • Medication impairing neutrophil function (e.g., omeprazole)
  • The most important independent predictor of recurrence is a positive family history.
GENERAL PREVENTION
Patient education regarding self-care (see “General Measures”); treatment and prevention are interrelated.
COMMONLY ASSOCIATED CONDITIONS
  • Usually normal immune system
  • Diabetes mellitus
  • Polymorphonuclear leukocyte defect (rare)
  • Hyperimmunoglobulin E-Staphylococcus sp. abscess syndrome (rare)
  • See “Risk Factors.”
image DIAGNOSIS
PHYSICAL EXAM
  • Painful erythematous papules/nodules (1 to 5 cm) with central pustules
  • Tender, red, perifollicular swelling, terminating in discharge of pus and necrotic plug
  • Lesions may be solitary or clustered.
DIFFERENTIAL DIAGNOSIS
  • Folliculitis
  • Pseudofolliculitis
  • Carbuncles
  • Ruptured epidermal cyst
  • Myiasis (larva of botfly/tumbu fly)
  • Hidradenitis suppurativa
  • Atypical bacterial or fungal infections
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
Obtain culture if with multiple abscesses marked by surrounding inflammation, cellulitis, systemic symptoms such as fever, or if immunocompromised.
Follow-Up Tests & Special Considerations
  • Immunoglobulin levels in rare (e.g., recurrent or otherwise inexplicable) cases
  • If culture grows gram-negative bacteria or fungus, consider polymorphonuclear neutrophil leukocyte functional defect.
Test Interpretation
Histopathology (although a biopsy is rarely needed)
  • Perifollicular necrosis containing fibrinoid material and neutrophils
  • At deep end of necrotic plug, in SC tissue, is a large abscess with a Gram stain positive for small collections of S. aureus.
image TREATMENT
GENERAL MEASURES
  • Moist, warm compresses (provide comfort, encourage localization/pointing/drainage) 30 minutes QID
  • If pointing or large, incise and drain: consider packing if large or incompletely drained.
  • Routine culture is not necessary for localized abscess in nondiabetic patients with normal immune system.
  • Sanitary practices: Change towels, washcloths, and sheets daily; clean shaving instruments; avoid nose picking; change wound dressings frequently; do not share items of personal hygiene (2)[B].
MEDICATION
First Line
  • Systemic antibiotics usually unnecessary, unless extensive surrounding cellulitis or fever
  • If suspecting MRSA, see “Second Line.”
  • P.391

  • If multiple abscesses, lesions with marked surrounding inflammation, cellulitis, systemic symptoms such as fever, or if immunocompromised: place on antibiotics therapy directed at S. aureus for 10 to 14 days.
    • Dicloxacillin (Dynapen, Pathocil) 500 mg PO QID or cephalexin 500 mg PO QID or clindamycin 300 mg TID, if penicillin-allergic
Second Line
  • Resistant strains of S. aureus (MRSA): clindamycin 300 mg q6h or doxycycline 100 mg q12h or trimethoprim-sulfamethoxazole (TMP-SMX DS) 1 tab q8-12h or minocycline 100 mg q12h
  • If known or suspected impaired neutrophil function (e.g., impaired chemotaxis, phagocytosis, superoxide generation), add vitamin C 1,000 mg/day for 4 to 6 weeks (prevents oxidation of neutrophils).
  • If antibiotic regimens fail:
    • May try PO pentoxifylline 400 mg TID for 2 to 6 months
    • Contraindications: recent cerebral and/or retinal hemorrhage; intolerance to methylxanthines (e.g., caffeine, theophylline); allergy to the particular drug selected
    • Precautions: prolonged prothrombin time (PT) and/or bleeding; if on warfarin, frequent monitoring of PT
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
Instruct patient to see physician if compresses are unsuccessful.
DIET
Unrestricted
PROGNOSIS
  • Self-limited: usually drains pus spontaneously and will heal with or without scarring within several days.
  • Recurrent/chronic: may last for months or years
  • If recurrent, usually related to chronic skin carriage of staphylococci (nares or on skin). Treatment goals are to decrease or eliminate pathogenic strain or suppress pathogenic strain.
    • Culture nares, skin, axilla, and perineum (culture nares of family members).
    • Mupirocin 2%: Apply to both nares BID for 5 days each month.
    • Culture anterior nares every 3 months; if failure, retreat with mupirocin or consider clindamycin 150 mg/day for 3 months.
  • Especially in recurrent cases, wash entire body and fingernails (with nailbrush) daily for 1 to 3 weeks with povidone-iodine (Betadine), chlorhexidine (Hibiclens), or hexachlorophene (pHisoHex soap), although all can cause dry skin.
REFERENCES
1. Demos M, McLeod MP, Nouri K. Recurrent furunculosis: a review of the literature. Br J Dermatol. 2012;167(4):725-732.
2. Fritz SA, Camins BC, Eisenstein KA, et al. Effectiveness of measures to eradicate Staphylococcus aureus carriage in patients with community-associated skin and soft-tissue infections: a randomized trial. Infect Control Hosp Epidemiol. 2011;32(9):872-880.
Additional Reading
&NA;
  • El-Gilany AH, Fathy H. Risk factors of recurrent furunculosis. Dermatol Online J. 2009;15(1):16.
  • Ibler KS, Kromann CB. Recurrent furunculosis-challenges and management: a review. Clin Cosmet Investig Dermatol. 2014;7:59-64.
  • McConeghy KW, Mikolich DJ, LaPlante KL. Agents for the decolonization of methicillin-resistant Staphylococcus aureus. Pharmacotherapy. 2009;29(3):263-280.
  • Rivera AM, Boucher HW. Current concepts in antimicrobial therapy against select gram-positive organisms: methicillin-resistant Staphylococcus aureus, penicillin-resistant pneumococci, and vancomycin-resistant enterococci. Mayo Clin Proc. 2011;86(12):1230-1243.
  • Wahba-Yahav AV. Intractable chronic furunculosis: prevention of recurrences with pentoxifylline. Acta Derm Venereol. 1992;72(6):461-462.
  • Winthrop KL, Abrams M, Yakrus M, et al. An outbreak of mycobacterial furunculosis associated with footbaths at a nail salon. N Engl J Med. 2002;346(18):1366-1371.
See Also
&NA;
Folliculitis; Hidradenitis Suppurativa
Codes
&NA;
ICD10
  • L02.92 Furuncle, unspecified
  • L02.12 Furuncle of neck
  • L02.429 Furuncle of limb, unspecified
Clinical Pearls
&NA;
  • Pathogens may be different in different localities. Keep up-to-date with the locality-specific epidemiology.
  • If few, furuncles/furunculosis do not need antibiotic treatment. If systemic symptoms (e.g., fever), cellulitis, or multiple lesions occur, oral antibiotic therapy is used.
  • Other treatments for MRSA include linezolid PO or IV and IV vancomycin.
  • Folliculitis, furunculosis, and carbuncles are parts of a spectrum of pyodermas.
  • Other causative organisms include aerobic (e.g., Escherichia coli, Pseudomonas aeruginosa, and Streptococcus faecalis), anaerobic (e.g., Bacteroides, Lactobacillus, Peptobacillius, and Peptostreptococcus), and Mycobacteria.
  • Decolonization (treatment of the nares with topical antibiotic) is only recommended if the colonization was confirmed by cultures because resistance is common and treatment is of uncertain efficacy.