Can sinus infections infect infraorbital (below the eye) epidermal cysts?

Sinus Infections Can Infect Infraorbital Epidermal Cysts

Yes, sinus infections can spread to and infect infraorbital epidermal cysts, particularly when the sinusitis involves the maxillary or ethmoid sinuses which are anatomically adjacent to the infraorbital region. 1 This complication represents an extension of infection beyond the sinus cavity into surrounding tissues.

Pathophysiology of Sinus-Related Infections

Sinus infections, particularly those involving the ethmoid and maxillary sinuses, can spread to adjacent structures through several mechanisms:

• Direct extension through thin bony walls (particularly the lamina papyracea separating ethmoid sinuses from the orbit)
• Spread via venous channels that lack valves
• Contiguous spread to nearby soft tissues

When sinusitis extends beyond the sinus cavity, it can cause:

1. Preseptal cellulitis (infection confined to tissues anterior to the orbital septum)
2. Postseptal cellulitis (infection behind the orbital septum)
3. Orbital abscess formation
4. Infection of adjacent structures, including epidermal cysts 1

Diagnostic Considerations

When an infraorbital epidermal cyst becomes infected in the context of sinusitis, clinical evaluation should include:

• Assessment for signs of orbital complications (proptosis, limitation of extraocular movements)
• Evaluation for sinusitis symptoms (nasal discharge, facial pain, headache)
• Examination of the cyst for signs of inflammation (erythema, tenderness, fluctuance)

Imaging is crucial for proper diagnosis:

• CT orbits with IV contrast is the most useful initial imaging for suspected orbital infection or extension from sinusitis 1
• This helps differentiate preseptal from postseptal involvement and identify any abscess formation
• It also reveals the relationship between the sinus infection and the epidermal cyst 1

Management Approach

Treatment should follow this algorithm:

1. For uncomplicated inflamed epidermal cysts:

   • Incision and drainage with culture
   • Avoid empiric antibiotics initially as nearly 50% of inflamed epidermal cysts do not grow pathogenic bacteria 2

2. For cysts with evidence of sinus infection involvement:

   • Appropriate antibiotic therapy targeting common sinus pathogens
   • Consider broader coverage if there are signs of orbital involvement
   • Surgical drainage may be necessary for both the sinus infection and the infected cyst

3. For cases with orbital complications:

   • Immediate contrast-enhanced CT scan to determine extent of infection 1
   • Aggressive antibiotic therapy
   • Surgical consultation for possible drainage of the sinus, orbit, and cyst

Important Clinical Considerations

• Epidermal cysts in the infraorbital region can mimic facial cellulitis when infected, as seen in case reports of maxillary sinus epidermoid cysts 3, 4
• The infection of an epidermal cyst can be the presenting sign of an underlying sinusitis
• Complications of untreated infection can be serious, including orbital cellulitis, cavernous sinus thrombosis, and intracranial spread 1

Pitfalls to Avoid

• Don't assume all inflamed infraorbital cysts require antibiotics - culture first when possible 2
• Don't miss underlying sinusitis - evaluate for sinus symptoms in patients with infraorbital cyst infections
• Don't delay imaging when there are signs of orbital involvement (proptosis, limited extraocular movements, vision changes) 1
• Don't rely solely on clinical findings to differentiate preseptal from postseptal involvement - imaging is essential 1

While epidermoid cysts within the maxillary sinus itself are rare, they have been reported and can become infected, mimicking sinusitis 3, 4. The anatomical proximity of the infraorbital region to the paranasal sinuses makes infection spread between these structures a clinically important consideration.