What is the best approach to diagnose allergy rhinitis?

How to Diagnose Allergic Rhinitis

Make the clinical diagnosis of allergic rhinitis when patients present with at least one of four cardinal symptoms (nasal congestion, runny nose, itchy nose, or sneezing) plus a history and physical exam consistent with an allergic cause—then confirm with specific IgE testing (skin or blood) only when empiric treatment fails, the diagnosis is uncertain, or you need to identify specific allergens to guide therapy. 1, 2

Initial Clinical Diagnosis

The diagnosis starts clinically and does not require testing in most cases. 1, 2

Cardinal Symptoms (Need ≥1 of These)

• Nasal congestion 1, 2
• Rhinorrhea (runny nose) 1, 2
• Nasal itching 1, 2
• Sneezing 1, 2

Essential History Elements

Obtain a systematic history addressing these specific domains—this remains your best diagnostic tool: 1, 2

Pattern and Timing:

• Duration and frequency of symptoms 1, 2
• Seasonal versus perennial presentation (seasonal exacerbations strongly suggest allergic rhinitis) 1, 2
• Age of onset (typically before age 20 in allergic rhinitis versus later onset in nonallergic) 1

Symptom Characteristics That Favor Allergic Rhinitis:

• Prominent itching and sneezing (much more common in allergic than nonallergic rhinitis) 1, 2
• Associated ocular symptoms (red, watery, itchy eyes) 1, 2
• Symptoms triggered by specific allergen exposures 1, 2

Red Flags for Alternative Diagnoses:

• Isolated postnasal drainage without other symptoms (less likely allergic) 1
• Unilateral symptoms (suggests structural problem, polyp, foreign body, or tumor) 1
• Symptoms triggered only by strong odors like perfume or smoke (suggests vasomotor rhinitis) 1
• Rhinorrhea only with eating (suggests gustatory rhinitis) 1

Additional History:

• Environmental and occupational exposures 1, 2
• Response to previous medications 1, 2
• Impact on quality of life, sleep, work/school performance 1, 2
• Comorbid conditions (asthma, atopic dermatitis, conjunctivitis) 1, 2
• Family history of allergic diseases 1, 2

In Children, Specifically Ask About:

• Sniffing, snorting, throat clearing 1
• Chronic mouth breathing, halitosis 1
• Dark circles under eyes, eye rubbing 1
• Poor appetite, learning problems, sleep disturbances, irritability 1

Physical Examination Findings

Focus on the nose but examine ears, eyes, throat, and lungs: 1, 2

Nasal Examination:

• Clear rhinorrhea (classic for allergic rhinitis) 1, 2
• Pale, edematous nasal mucosa (though this can occur in nonallergic rhinitis too) 1, 2
• Turbinate hypertrophy 2
• Assess nasal patency and look for anatomical obstruction 1, 2

Associated Findings:

• Red, watery eyes with conjunctival injection 1, 2
• Allergic shiners (dark circles under eyes) 2
• Transverse nasal crease from chronic rubbing 1

Critical Point: Mucosal appearance alone cannot distinguish allergic from nonallergic rhinitis, as both can show pallor, edema, or erythema. 1 The diagnosis requires correlation of history with physical findings.

When to Perform Confirmatory IgE Testing

Do NOT routinely test everyone. 1 Perform specific IgE testing (skin testing preferred, or blood testing) in these situations: 1, 2

1. Inadequate response to empiric treatment 1, 2
2. Uncertain diagnosis 1, 2
3. Need to identify specific causative allergens to guide targeted environmental controls or immunotherapy 1, 2

Testing Methods

• Skin testing is preferred over blood testing (higher sensitivity) 2, 3
• In vitro specific IgE blood tests have approximately 70-75% sensitivity compared to skin testing 2
• The diagnosis of allergic rhinitis requires both: positive history of symptoms after allergen exposure AND positive specific IgE testing 1, 2

What NOT to Do

• Do not routinely perform sinus imaging in patients with symptoms consistent with allergic rhinitis 1
• Do not rely on physical examination findings alone—they cannot definitively distinguish allergic from nonallergic rhinitis 1

When to Refer to Allergist/Immunologist

Consider referral when: 2

• Prolonged symptoms despite appropriate treatment
• Complications develop
• Comorbid asthma present
• Need for systemic corticosteroids
• Symptoms significantly impair quality of life or function
• Patient needs allergen immunotherapy evaluation

Practical Algorithm

1. Patient presents with nasal symptoms → Obtain detailed history focusing on cardinal symptoms, timing, triggers, and associated features
2. Perform focused physical examination → Look for clear rhinorrhea, pale nasal mucosa, ocular findings
3. History + exam consistent with allergic cause? → Make clinical diagnosis of allergic rhinitis 1
4. Initiate empiric treatment (intranasal corticosteroids first-line) 1
5. Adequate response? → Continue treatment, no testing needed
6. Inadequate response OR uncertain diagnosis OR need specific allergen identification? → Perform or refer for specific IgE testing 1, 2

Common Pitfall: Many clinicians over-test. In a practice with high baseline prevalence of allergic rhinitis, empiric treatment is justified without testing since medications have minimal toxicity. 3 Reserve testing for the specific indications above.