Blue Nasal Discharge: Pseudomonas aeruginosa Infection – Signs & Treatment

Clinical Significance

Blue or blue-green nasal discharge is a classic sign of Pseudomonas aeruginosa infection. The pigment pyocyanin (blue) and pyoverdine (yellow-green) produce the characteristic color.

Typical Clinical Scenarios

• Hospital-acquired sinusitis (especially ICU, prolonged intubation).
• Chronic sinusitis in cystic fibrosis, bronchiectasis, immunocompromise.
• Contact lens–associated keratitis (ocular, not nasal).
• External otitis ("swimmer's ear") – green-blue discharge.
• Wound infections, burn infections, ventilator-associated pneumonia.

Associated Symptoms

• Purulent, foul-smelling discharge (nasal, ear, wound).
• Facial pain/pressure, congestion, anosmia.
• Fever, malaise (if systemic).
• In CF: chronic cough, declining lung function.

Diagnosis

• Gram stain: Gram-negative rods.
• Culture: P. aeruginosa grows on MacConkey (lactose non-fermenter), cetrimide agar (selective).
• PCR panels (syndromic testing).

Treatment

• Topical: Nasal irrigation, aminoglycoside/colistin nebulization (sinusitis).
• Systemic (invasive/severe): Anti-pseudomonal β-lactam (piperacillin-tazobactam, ceftazidime, cefepime, meropenem) ± aminoglycoside or fluoroquinolone. Combination therapy for bacteremia/neutropenia.
• Source Control: Drain abscess, remove foreign body (catheter, stent).

Resistance Concern

P. aeruginosa has intrinsic resistance (efflux pumps, low permeability) and acquires resistance rapidly. Susceptibility testing mandatory.