Sinusitis vs. Allergies: Different Causes of Similar Congestion

Allergic rhinitis causes congestion, sneezing, and clear discharge due to an immune overreaction to allergens. Sinusitis is inflammation or infection of the sinus cavities, often following a cold or allergies, producing thicker discharge and facial pain. Allergies can predispose to sinusitis.

Key Differences at a Glance

Cause
Sinusitis
Infection (bacterial or viral) of sinus cavities
Allergies
Immune reaction to pollen, dust, mold, pet dander
Discharge
Sinusitis
Thick, yellow-green nasal discharge
Allergies
Clear, watery nasal discharge
Pain
Sinusitis
Facial pain and pressure over sinuses, worse when bending forward
Allergies
Mild pressure; no significant facial pain
Fever
Sinusitis
May have fever (bacterial sinusitis)
Allergies
No fever

Shared Symptoms

  • Nasal congestion
  • Post-nasal drip
  • Reduced sense of smell

Unique Indicators

ONLY Sinusitis
  • Facial pain/pressure over cheeks and forehead
  • Thick colored discharge
  • Fever
  • Tooth pain
ONLY Allergies
  • Itchy eyes, nose, throat
  • Sneezing fits
  • Seasonal pattern
  • Clear discharge

Professional Diagnosis

Allergies: clinical history, skin prick tests, serum IgE. Sinusitis: clinical diagnosis based on symptom duration and character; CT scan for chronic or complicated cases.

Treatment for Sinusitis

Nasal saline irrigation, nasal corticosteroid sprays, decongestants. Antibiotics only for bacterial sinusitis lasting beyond 10 days or with severe symptoms.

Treatment for Allergies

Antihistamines, nasal corticosteroid sprays, allergen avoidance, and immunotherapy (allergy shots) for long-term management.

When to See a Doctor

See a doctor if symptoms persist beyond 10 days without improvement, if you develop high fever and severe facial pain, or if symptoms recur frequently.

Not sure which one you have?

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Medically Reviewed for Accuracy

Medical Advisory Board
Last reviewed: March 20, 2026

Content is aligned with established clinical guidelines from authoritative medical institutions, including MedlinePlus (U.S. National Library of Medicine), the CDC, the NIH, and the NHS. All content is reviewed by our medical advisory board for accuracy and safety.