[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Abscess, furuncle and carbuncle

[Conditions](https://durgical.com/en/conditions/) · [Dermatology](https://durgical.com/en/conditions/)

# Abscess, furuncle and carbuncle

Painful, pus-filled lumps in the [skin](https://durgical.com/en/anatomy/skin/), usually from staph bacteria. Large ones need draining; a cluster of linked boils is called a carbuncle.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Skin](https://durgical.com/en/anatomy/skin/)
- [Neck lymph nodes](https://durgical.com/en/anatomy/lymph-nodes-of-neck/)

## Why it happens

- [Outcomes of acute inflammation: resolution, abscess, scar or chronic inflammation](https://durgical.com/en/general-pathology/outcomes-of-acute-inflammation-resolution-abscess-scar-or-chronic-inflammation/)
- [When leukocytes injure tissue: proteases, oxidants and NETs](https://durgical.com/en/general-pathology/when-leukocytes-injure-tissue-proteases-oxidants-and-nets/)
- [Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer](https://durgical.com/en/general-pathology/patterns-of-acute-inflammation-serous-fibrinous-purulent-abscess-ulcer/)
- [Leukocyte recruitment: rolling, adhesion, transmigration, chemotaxis](https://durgical.com/en/general-pathology/leukocyte-recruitment-rolling-adhesion-transmigration-chemotaxis/)
- [Inflammation: the cardinal signs and its five steps](https://durgical.com/en/general-pathology/inflammation-the-cardinal-signs-and-its-five-steps/)
- [Special stains in diagnosis: Congo red, Prussian blue, PAS, Ziehl–Neelsen, Gram](https://durgical.com/en/general-pathology/special-stains-in-diagnosis-congo-red-prussian-blue-pas-ziehl-neelsen-gram/)

## Show 1 more

- [Hair follicles, sebaceous and sweat glands, nails](https://durgical.com/en/histology/hair-follicles-sebaceous-and-sweat-glands-nails/)

## What it is

Purulent skin and soft-tissue infections. A skin abscess is a collection of pus in the dermis and subcutaneous tissue. A furuncle (boil) is a deep infection of a single hair follicle; a carbuncle is a group of furuncles joined under the skin with several draining points.

## Who gets it

Very common in all ages and a frequent reason for emergency and primary-care visits. Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has become a leading cause in the Americas, including Colombia and other Latin American countries. Outbreaks occur in prisons, military units, contact sports teams and households.

## Causes

- Staphylococcus aureus in most cases, including MRSA
- Streptococci and mixed flora, especially in perineal or perianal sites and in people who inject drugs
- Entry through hair follicles, small cuts, insect bites or injection sites

## Risk factors

- Nasal or skin carriage of S. aureus
- Diabetes mellitus, obesity and immunosuppression
- Close contact, crowding, shared towels, razors or sports equipment
- Injection drug use
- Poor hygiene, friction and sweating (armpits, buttocks, neck)
- Previous MRSA infection or recent hospitalisation

## Pathophysiology

Bacteria invade a follicle or a break in the skin and attract neutrophils. Bacterial toxins (for example the Panton-Valentine leukocidin of many community MRSA strains) kill tissue and white cells, and the resulting pus is walled off by a fibrin capsule. The capsule limits spread but also keeps antibiotics from penetrating well, which is why drainage, not antibiotics, is the key treatment.

## Classification

- Furuncle: single follicle, often on the neck, face, armpit or buttocks
- Carbuncle: several connected furuncles, typically on the nape of the neck or back
- Simple skin abscess
- Recurrent furunculosis
- Severity: mild (no systemic signs), moderate, severe (systemic toxicity or immunosuppression)

## Symptoms and signs

- Red, warm, painful nodule that becomes soft and fluctuant
- A yellow or white point (pustule) on top that may drain pus
- Surrounding redness and swelling
- Several draining openings in a carbuncle
- Fever and malaise, more common with carbuncles or large abscesses

## Red flags

- Fever, tachycardia, hypotension or confusion (sepsis)
- Pain out of proportion to findings, rapid spread, crepitus or skin necrosis (necrotising fasciitis)
- Furuncle on the central face (risk of [cavernous sinus](https://durgical.com/en/anatomy/cavernous-sinus/) thrombosis)
- Abscess in the hand, perineum or over a joint or near the [spine](https://durgical.com/en/anatomy/region/spine/)
- Recurrent abscesses or infection in an immunosuppressed person or someone who injects drugs (consider endocarditis)

## Diagnosis

**Clinical**
Clinical: a tender, fluctuant nodule, sometimes with a central pustule; look for spreading cellulitis and systemic signs.

**Tests**
Gram stain and culture of pus after drainage, especially for recurrent, severe or treatment-failing infections, to identify MRSA and guide antibiotics. Blood cultures and laboratory tests if systemic signs. Check glucose in recurrent cases.

**Imaging**
Bedside ultrasound confirms a fluid collection when it is unclear whether pus is present and guides drainage.

## Differential diagnosis

- Cellulitis without abscess
- Inflamed epidermoid cyst
- Hidradenitis suppurativa (recurrent nodules in armpits and groin)
- Septic bursitis or septic arthritis
- Myiasis (furuncular) in travellers or rural areas

## Goal of treatment

Drain the pus, control infection and its spread, prevent recurrence and transmission, and recognise severe infection early.

## Treatment

**Conservative**
Small furuncles: warm, moist compresses to promote spontaneous drainage; do not squeeze.

**Procedure**
Incision and drainage is the main treatment for fluctuant abscesses and carbuncles, with breaking of loculations and wound care.

**Medical**
Antibiotics are added for systemic signs, surrounding cellulitis, large or multiple abscesses, difficult sites, extremes of age or immunosuppression; empirical choices cover MRSA (e.g. trimethoprim-sulfamethoxazole, doxycycline or clindamycin; vancomycin intravenously for severe infection), adjusted to culture.

**Follow-up**
Wound checks, hand hygiene and contact precautions for draining wounds; decolonisation (nasal mupirocin, antiseptic washes) for recurrent infection.

## Drugs for this condition

- [Dalbavancin](https://durgical.com/en/pharmacology/dalbavancin/)

## Complications

- Cellulitis and lymphangitis
- Bacteraemia, sepsis and seeding to bones, joints or heart valves
- Cavernous sinus thrombosis from facial furuncles
- Recurrence and spread to household contacts
- Scarring

## Prognosis

Most abscesses heal well after drainage, usually within one to two weeks. Recurrence is common with MRSA colonisation, diabetes or ongoing exposure.

## Prevention

- Hand hygiene and not sharing towels, razors or sports gear
- Covering draining wounds until healed
- Glycaemic control in diabetes
- Decolonisation for patients with recurrent infection

## Test yourself

Think of the answer, then tap the question to see it.

## What is the most common cause of skin abscesses and furuncles?

Staphylococcus aureus, increasingly community-acquired MRSA.

## What is the key treatment of a fluctuant skin abscess?

Incision and drainage; antibiotics are added only in selected cases.

## How does a carbuncle differ from a furuncle?

A carbuncle is several interconnected infected follicles with multiple draining points, usually on the nape or back.

## Why is a furuncle on the central face of concern?

Infection can spread through valveless facial veins to the cavernous sinus.

## Which test helps when it is unclear whether a red swelling contains pus?

Bedside ultrasound.

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## Related conditions

- [Cellulitis of the leg](https://durgical.com/en/conditions/cellulitis-of-the-leg/)
- [Impetigo](https://durgical.com/en/conditions/impetigo/)
- [Hidradenitis suppurativa](https://durgical.com/en/conditions/hidradenitis-suppurativa/)
- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)
- [Type 2 diabetes mellitus](https://durgical.com/en/conditions/type-2-diabetes-mellitus/)
- [Infective endocarditis](https://durgical.com/en/conditions/infective-endocarditis/)
- [Osteomyelitis](https://durgical.com/en/conditions/osteomyelitis/)
- [Necrotizing soft tissue infection (necrotizing fasciitis, gas gangrene)](https://durgical.com/en/conditions/necrotizing-soft-tissue-infection/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Boils](https://medlineplus.gov/ency/article/001474.htm) (MedlinePlus, US National Library of Medicine, 2026); [Carbuncle](https://medlineplus.gov/ency/article/000825.htm) (MedlinePlus, US National Library of Medicine, 2026); [Methicillin-resistant Staphylococcus aureus (MRSA) Basics](https://www.cdc.gov/mrsa/about/index.html) (Centers for Disease Control and Prevention (CDC), 2026).

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Source: https://durgical.com/en/conditions/abscess-furuncle-and-carbuncle/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/abscess-furuncle-and-carbuncle/