Furunculosis

Management Strategy

The infectious agent most commonly implicated is Staphylococcus aureus ; methicillin-resistant strains of S. aureus (MRSA) are now recognized as the dominant isolate overall. In recent years, the designations of community-acquired MRSA (CA-MRSA) versus hospital-acquired MRSA (HA-MRSA) have become blurred due to a convergence in both antibiotic susceptibility profiles and risk of sequelae. There are rare reports of dissemination causing epidural abscess, bacterial endocarditis, and pulmonary infection.

Group A beta-hemolytic Streptococcus , Gram-negative bacteria, and yeast-forms should remain in the differential diagnosis. In addition, Mycobacterium spp., especially M. fortuitum , have been implicated in furunculosis in patients using footbaths in beauty salons.

Nasal, pharyngeal, axillary, perineal, and rectal pathogen carriage is implicated in recurrent disease. In rare cases, patients with impaired neutrophil function and immunodeficiency syndromes, such as common variable immunodeficiency and hyper-IgE syndrome, also present with recurrent ‘cold abscess’ furunculosis, .

Isolated lesions should be incised and drained . Multiple, mostly observational, studies indicate high postsurgical cure rates (85%–90%) whether or not an active antibiotic is used. Therefore, according to the Centers for Disease Control (2006) and Infectious Diseases Society of America (2011), empiric antibiotics should be reserved for those with:

• Severe or extensive disease (e.g., involving multiple sites of infection)

• Rapid progression in presence of associated cellulitis

• Signs and symptoms of systemic illness

• Associated comorbidities/immunosuppression (diabetes mellitus, human immunodeficiency virus, neoplasm)

• Extremes of age

• Abscess in area difficult to drain completely (e.g., face, hand, and genitalia)

• Associated septic phlebitis

• Lack of response to incision and drainage alone

Swabs of any purulent discharge should be collected for bacterial culture; antibiotic therapy may be redirected based on sensitivities and clinical scenario. Acid-fast staining and culture may be warranted if a temporal relationship to a pedicure is noted. Currently, antibiotics carrying a Food and Drug Administration (FDA) indication for use against MRSA include linezolid, ceftaroline (‘advanced’-generation cephalosporin), telavancin (similar to vancomycin), tigecycline (derivative of minocycline), and teicoplanin . Other antibiotics with anti-MRSA activity include trimethoprim-sulfamethoxazole (TMP-SMX), daptomycin, vancomycin, doxycycline, minocycline, clindamycin, rifampin, and quinupristin–dalfopristin. Evidence of nasal carriage of staphylococci should be sought in those with recurrent disease and eradicated with either oral rifampicin (not as monotherapy) or nasal mupirocin or fusidic acid.