What are the differential diagnoses for a red nose?

Differential Diagnosis for Red Nose

A red nose is most commonly caused by inflammatory conditions including rosacea with telangiectasias, rhinitis (allergic or non-allergic), acute rhinosinusitis, rhinitis medicamentosa from topical decongestant overuse, or less commonly granulomatous diseases and tumors. 1

Primary Inflammatory and Vascular Causes

Rosacea with telangiectasias is a leading cause of persistent nasal erythema, characterized by visible dilated blood vessels on the nasal skin surface. 2 This condition responds well to laser therapy when telangiectasias are the predominant feature. 2

Rhinitis medicamentosa should be suspected in patients with rebound nasal congestion and erythema following overuse of intranasal α-adrenergic decongestants or cocaine. 3 This represents a critical diagnosis to identify, as continued use perpetuates the problem.

Rhinitis Syndromes

Allergic Rhinitis

• Key distinguishing features include nasal itching, sneezing, clear rhinorrhea, and often ocular symptoms (watery discharge, conjunctival injection). 3, 4
• Symptoms may be seasonal (outdoor allergens like pollens) or perennial (indoor allergens like dust mites, animal dander). 3, 5
• Physical examination reveals clear rhinorrhea and bluish or pale swelling of nasal mucosa. 3
• Family history of atopic disease strengthens the diagnosis. 3

Non-Allergic Rhinitis

• Includes vasomotor rhinitis and non-allergic rhinitis with eosinophilia syndrome (NARES). 4
• Symptoms develop on exposure to irritants (smoke, fumes, chemicals) rather than specific allergens. 3
• Lacks the characteristic itching and sneezing pattern of allergic rhinitis. 4

Infectious Causes

Acute Viral Rhinosinusitis

• Suspect when symptoms last less than 10 days without worsening. 3, 6
• Presents with clear or cloudy nasal drainage, nasal obstruction, and facial pressure. 3

Acute Bacterial Rhinosinusitis

• Diagnose when symptoms persist ≥10 days without improvement or worsen within 10 days after initial improvement (double worsening). 3, 6
• Characterized by purulent (cloudy or colored) nasal drainage plus nasal obstruction or facial pain-pressure-fullness. 3
• Physical examination may reveal erythema or edema over the involved cheek or periorbital area. 3

Chronic Rhinosinusitis

• Requires symptoms persisting ≥12 weeks with objective evidence of inflammation on nasal endoscopy or CT. 4, 6
• Cannot be diagnosed on symptoms alone. 6

Drug-Induced Causes

Multiple medications can cause nasal erythema and rhinitis symptoms, including:

• ACE inhibitors
• Phosphodiesterase-5 inhibitors
• α-receptor antagonists
• Aspirin and NSAIDs 3

A thorough medication history is essential, including over-the-counter preparations. 3

Serious Conditions Requiring Further Investigation

Red Flags Warranting Biopsy or Advanced Imaging

• Unilateral symptoms (rhinorrhea, nasal blockage)
• Epistaxis
• Severe headache or anosmia
• Cutaneous infiltration suggesting granulomatous or tumoral processes 3, 1

These atypical features may indicate:

• Sinonasal tumors
• Granulomatous diseases
• CSF rhinorrhea (if clear rhinorrhea is refractory) 3

Diagnostic Approach

Initial Evaluation

1. Characterize the pattern: Seasonal vs. perennial vs. episodic exposure-associated symptoms 3, 4
2. Assess associated symptoms: Itching (suggests allergic), purulent discharge (suggests bacterial), clear discharge with irritant exposure (suggests non-allergic) 3, 4
3. Physical examination: Inspect for nasal mucosa appearance (pale/bluish in allergic rhinitis), purulent discharge, erythema/edema of overlying skin 3
4. Medication review: Identify potential drug-induced causes 3

When to Perform Allergy Testing

• Specific IgE testing (skin tests preferred) is indicated when history suggests seasonal or environmental triggers, or when diagnosis is uncertain. 3, 6
• Testing helps target avoidance measures and immunotherapy. 3

When to Obtain Imaging

• CT imaging should be reserved for chronic cases failing medical therapy, suspected complications, or when diagnosis is uncertain. 4, 6
• Nasal endoscopy is superior to anterior rhinoscopy for evaluating inflammation. 4, 6

Common Pitfalls to Avoid

• Failing to distinguish between viral, bacterial, and non-infectious causes based on symptom duration and character 4
• Overlooking medication-induced rhinitis, particularly rhinitis medicamentosa from decongestant overuse 3
• Missing serious pathology by not investigating unilateral symptoms, epistaxis, or severe headache 3
• Diagnosing chronic rhinosinusitis on symptoms alone without objective evidence of inflammation 4, 6