Folliculitis, Furuncles, and Carbuncles
Folliculitis is superficial inflammation or infection of hair follicles, while furuncles are deeper follicular infections causing small abscesses, and carbuncles are interconnected groups of furuncles forming a larger inflammatory mass.
This updated UKMLA guide to folliculitis, furuncles (boils), and carbunclesis based on PCDS guidance and NICE CKS, which covers causes, risk factors, symptoms, diagnosis, and management
Definition
| Condition | Definition |
|---|---|
| Folliculitis | Superficial inflammation / infection of the hair follicles |
| Furuncle (boil) | Deep infection of a hair follicle, causing a small abscess |
| Carbuncle | Interconnection of multiple furuncles into an inflammatory mass |
Causes
Most commonly caused by Staphylococcus aureus infection
Pseudomonas aeruginosa classically causes folliculitis following exposure to contaminated water, such as hot tubs, Jacuzzis, or swimming pools.
Pseudofolliculitis is a non-infectious inflammatory reaction caused by ingrown hairs (see below for more information).
Risk Factors
- Males
- Shaving
- Tight clothing
- Sweating
- Participation in contact spots
- Poor hygiene
- Living in overcrowded conditions
- Immunosuppression (e.g. diabetes, HIV infection)
- Obesity
- Pre-existing skin conditions (e.g. atopic eczema)
Clinical Features
| Condition | Clinical features |
|---|---|
| Folliculitis | Small peri-follicular inflammatory papules or pustules on skins with hair follices:
Pseudofolliculitis is a non-infectious inflammatory reaction caused by ingrown hairs. Most commonly occurring after shaving (esp. the bread region)
|
| Furuncle (boil) | Location: skin with hair follicles like the face, axilla, and buttocks
|
| Carbuncle | Location: nape of the neck, back, thigh
|
Eosinophilic folliculitis is a specific type of folliculitis that is typically seen in HIV and other immunosuppressed patients
- Often starts at the face, and affects the neck and upper trunk
- Intensely pruritic
- Slightly different morphology: papulopustules with central clearing, coalescing pustular/papular rash
- Swabs are sterile (non-bacterial origin)
Investigation and Diagnosis
Primarily a clinical diagnosis
Skin swabs of expressed pus for MC&S can help guide antimicrobial treatment.
Management
Folliculitis
| General / conservative management | Advise on measures that target risk factors, including paracetamol or ibuprofen for pain relief
If folliculitis is related to shaving and other hair-removal techniques:
|
| Pharmacological management | Treatment for confirmed staphylococcal infection (most common)
Mild topical steroids may be used for areas of inflammation, but should be avoided if caused by an infection |
Furuncles and Carbuncles
Provide self-care advice to target risk factors, including paracetamol or ibuprofen for pain relief
| Indications for same-day incision and drainage |
|
| Management of furuncles NOT requiring incision and drainage | Self-care measures
Indications for oral antibiotics (1st line: flucloxacillin, 2nd line: erythromycin or clarithromycin)
|