Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Etiology | Clinical features | Treatment | Clinical images | Microscopic (histologic) description | Differential diagnosisCite this page: Do HK. Carbuncle. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorcarbuncle.html. Accessed November 27th, 2024.
Definition / general
- Deep form of bacterial folliculitis involving several hair follicles, often due to Staphylococcus aureus, which can be cultured from skin
Terminology
- Also known as boils
- Furuncle: small abscess exuding purulent material, involving skin and subcutis in areas with hair follicles
- Carbuncle: aggregate of connected furuncles, involves multiple hair follicles
Epidemiology
- Most individuals with carbuncles are otherwise healthy and have good personal hygiene, but they are among the 10 - 20% of population that are Staphylococcus aureus carriers on surface of skin
- Common in obese patients
- Carbuncles may occur in patients with immune deficiency, anemia, diabetes or iron deficiency
Sites
- Staphylococcus aureus is most commonly found in intertriginous regions (where two skin areas may touch or rub together) of nostrils, armpits, groin and intergluteal cleft
Etiology
- Staphylococcus aureus is present in patients in intertriginous regions, but may be transferred to other sites by scratching
- Tiny nicks or scratches in the skin can inoculate the bacteria into the wall of a hair follicle, a weak point in the skin
- Once innoculated, bacteria cause a boil, which runs its usual infectious course in about 10 days
Clinical features
- Painful localized bacterial infection of skin and subcutis, usually with several openings through which pus is discharged
- Tender, swollen red papules or pustules
Treatment
- Antiseptic cleanser, like povidone-iodine or chlorhexidine is used daily for several weeks to clean carbuncle
- Topical antibiotics include erythromycin BID and clindamycin BID to affected area until clear
- Note: verify current drug dosages before use (eMedicine)
- Oral antibiotics include:
- Cephalexin (adult) 1 - 4 g/day divided BID or QID x 10 - 14 days; (children) 25 - 50 mg/kg/day PO divided q6H for mild to moderate infection; 50 - 100 mg/kg/day divided q6H for severe infection; not to exceed 4g/day for any age
- Dicloxacillin (adult or children > 40 kg) 125 - 500 mg q6h x 10 - 14 days; (children < 40 kg): 12.5 - 50 mg/kg/d PO divided q6h
- Erythromycin (adult) 500 mg BID or 330mg q8hr x 10 - 14 days
- Clindamycin (adult) 150 - 450 mg q6 - 8h x 10 - 14 days; (children) 10 - 30 mg/kg/day q6 - 8h
- Minocycline (adult) 100 mg BID x 10 - 14 days
- Rifampin (adult) 600 mg qD x 10 days; (children) 15 mg/kg/day divided BID x 10 days
- Ciprofloxacin (adult): 250 - 750 mg BID x 10 - 14 days
- In recurrent cases, obtain nasal culture of patient and family members to look for Staphylococcus aureus colonization
- If patient is Staphylococcus aureus nasal carrier, consider applying topical antibiotic like mupirocin ointment to nostrils twice daily for 5 days (Wikipedia)
- If family members are nasal carriers, consider mupirocin ointment or rifampin 600 mg daily for 10 days
- Consider checking nasal swab for MRSA or culture for sensitivity for treatment failure
- Prevention:
- Good hygiene including bathing, hand-washing, keeping nails short and clean
- Avoid close shaving until lesions are completely resolved
- Change disposable razors daily or clean electric razor heads daily
- Wear loose-fitting clothes (tight-fitting clothes may cause occlusion); change clothes daily
- In obese patients, weight reduction will be beneficial
Clinical images
Images hosted on other servers:
Various images
Microscopic (histologic) description
- Inflammatory cells, predominantly neutrophils, within the wall and ostia of the hair follicle, creating a follicular-based pustule
- Inflammation can be either limited to the superficial follicle, primarily involving the infundibulum, or can affect both the superficial and deep aspects of the follicle
- Deep folliculitis can arise from the chronic lesions of superficial folliculitis or from lesions that are manipulated or scratched; may cause scarring
Differential diagnosis
- Abscess / furuncle
- Folliculitis: tender pustule that involves the hair follicle
- Irritated epidermal inclusion cyst
