(See also Overview of Bacterial Skin Infections Overview of Bacterial Skin Infections Bacterial skin infections can be classified as skin and soft tissue infections (SSTI) and acute bacterial skin and skin structure infections (ABSSSI). SSTI include Carbuncles Ecthyma Erythrasma... read more .)
Both furuncles and carbuncles may affect healthy young people but are more common among the obese, the immunocompromised (including those with neutrophil defects), older people, and possibly those with diabetes. Clustered cases may occur among those living in crowded quarters with relatively poor hygiene or among contacts of patients infected with virulent strains. Predisposing factors include bacterial colonization of skin or nares, hot and humid climates, and occlusion or abnormal follicular anatomy (eg, comedones in acne). Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause.
Furuncles are common on the neck, breasts, face, and buttocks. They are uncomfortable and may be painful when closely attached to underlying structures (eg, on the nose, ear, or fingers). Appearance is a nodule or pustule that discharges necrotic tissue and sanguineous pus.
Carbuncles are clusters of furuncles that are subcutaneously connected. They may be accompanied by fever and prostration.
Diagnosis of Furuncles and Carbuncles
Culture of lesion
Diagnosis is by examination. Material for culture should be obtained.
Treatment of Furuncles and Carbuncles
Often antibiotics effective against MRSA
Abscesses are incised and drained. Intermittent hot compresses are used to facilitate drainage. Antibiotics, when used, should be effective against MRSA MRSA and purulent or complicated cellulitis Cellulitis is acute bacterial infection of the skin and subcutaneous tissue most often caused by streptococci or staphylococci. Symptoms and signs are pain, warmth, rapidly spreading erythema... read more , pending culture and sensitivity test results. In afebrile patients, treatment of a single lesion < 5 mm requires no antibiotics. Systemic antibiotics are recommended for the following:
Lesions > 5 mm or < 5 mm that do not resolve with drainage
Evidence of expanding cellulitis
Treatment choices include trimethoprim/sulfamethoxazole (TMP/SMX) 160/800 mg to 320/1600 mg orally 2 times a day, clindamycin 300 to 600 mg orally every 6 to 8 hours, and doxycycline or minocycline 100 mg orally every 12 hours.
Inpatients with furunculosis in hospital settings where MRSA is prevalent may require isolation from other inpatients and treatment as recommended for cellulitis Treatment Cellulitis is acute bacterial infection of the skin and subcutaneous tissue most often caused by streptococci or staphylococci. Symptoms and signs are pain, warmth, rapidly spreading erythema... read more based on culture results.
Furuncles frequently recur and can be prevented by applying liquid soap containing either chlorhexidine gluconate with isopropyl alcohol or 2 to 3% chloroxylenol and by giving maintenance antibiotics over 1 to 2 months. Patients with recurrent furunculosis should be treated for predisposing factors such as obesity, diabetes, occupational or industrial exposure to inciting factors, and nasal carriage of S. aureus or MRSA colonization.
Suspect a furuncle if a nodule or pustule involves a hair follicle and discharges necrotic tissue and sanguineous pus, particularly if on the neck, breasts, face, or buttocks.
Culture furuncles and carbuncles.
Prescribe antibiotics effective against methicillin-resistant Staphylococcus aureus (MRSA) for patients who are immunocompromised, febrile, or at risk of endocarditis, or if lesions do not resolve with drainage or are > 5 mm, multiple, or expanding.