Infected Sebaceous Cyst

Red flags

  • Hard, fixed mass +/- suspicious mucosal lesion or aerodigestive tract
  • Impending airway disaster triad
  • Trismus
  • Spreading cellulitis or rapidly increasing neck swelling

 

When to involve the ENT registrar

  • Immediately: Suspicion of deep neck space infection ie adverse signs and sepsis
  • Soon: Large abscess requiring formal surgical drainage in operating theatre

 

Assessment and recognition

The diagnosis is clinical and comes with experience.

  • Cysts are firm but mobile (see Fig. 1 below)
  • They are in the skin itself, rather than deep to it
  • They transilluminate a little at best
  • There is frequently a yellow/white central punctum; a foul cheesy material may discharge from this
  • They are usually painless unless infected; If infected, they will be cellulitic and very painful

The presence of trismus or other adverse signs suggests something more complex than an infected sebaceous cyst. Infected cysts are very painful and can sometimes even cause pyrexia, but they do not cause trismus, dysphagia or other aerodigestive tract signs.

Ensure you perform a full head and neck as well as general medical examination.

Figure 1. A non-infected sebaceous cyst in a typical area, the nape of the neck.

Figure 1. A non-infected sebaceous cyst in a typical area, the nape of the neck.

Differential diagnosis

See Overview of Neck Lumps

 

IMMEDIATE & OVERNIGHT Management 

Infected cysts should be drained as soon as possible whereas non-infected cysts – even large ones –  should not as there is a risk of introducing infection. If bothersome, ENT surgeons will excise non-infected cysts electively.

If clinical proven to be infected sebaceous cysts, those on: 

  • the lobule of the ear
  • on the bony scalp around the ear
  • around the hairline (nape) of the neck

can be drained with a wide gauge needle and a 10ml syringe. (There are no important structures in the lobule, otherwise ENT surgeons would have to do all the ear piercings!).  

Aspiration brings significant relief – please consider it if the patient is not due to see an ENT surgeon within a few hours. Local anaesthetic can be instilled but usually this is as painful as needle aspiration. Be wary of aspirating large neck swellings in the anterior triangles. 

Patients can be discharged on oral antibiotics to cover skin pathogens.  Arrange follow-up in the ENT emergency clinic in 2-3 days.

Figure 2. Infected sebaceous cyst of the nape of the neck, with central punctum discharging cheesy or pus-like material. If examination revealed this to be non-pulsatile and confined to the skin, immediate aspiration would bring significant relief.

Figure 2. Infected sebaceous cyst of the nape of the neck, with central punctum discharging cheesy or pus-like material. If examination revealed this to be non-pulsatile and confined to the skin, immediate aspiration would bring significant relief.

Further management

Once the infection has settled, the patient may choose to have an elective excision of the cyst remnant, as infection will recur.

 

 

 

Page last reviewed: 3 March 2017