Summary
Allergic rhinitis is an acute or chronic inflammation of the nasal mucosa caused by a type 1 hypersensitivity reaction to an inhaled allergen (e.g., dust, animal dander, mold spores, plant pollen). It is the most common form of rhinitis and is associated with other allergic conditions such as atopic dermatitis and asthma. Clinical manifestations of allergic rhinitis include nasal congestion, rhinorrhea, sneezing, and postnasal drip. Exacerbation of allergic rhinitis symptoms may occur in certain seasons or with exposure to certain allergens. Allergic rhinitis is typically diagnosed based on clinical features. Allergen testing helps determine the causative allergen and may also be used to confirm the diagnosis if there is clinical uncertainty. Initial management involves allergen and irritant avoidance and pharmacotherapy with intranasal corticosteroids or oral or intranasal antihistamines. Allergen immunotherapy may be considered if initial treatment does not provide adequate symptom relief.
Epidemiology
Etiology
Allergic rhinitis is defined as an acute or chronic rhinitis that is caused by exposure to an inhaled allergen (e.g., dust, animal dander, mold spores, plant pollen).
- Etiology: type I hypersensitivity reaction (an IgE-mediated process) [3]
-
Risk factors [4][5]
- Genetic predisposition
- Family history of allergies and/or atopy
- Associated allergic conditions
- Birth during the pollen season
- Firstborn child [6]
- Early use of antibiotics, formula, or solids [7]
- Exposure to indoor allergens including maternal smoking in the first year of life [2]
Clinical features
- Recurrent episodes of sneezing, nasal congestion, rhinorrhea, and postnasal drip
- Itchy nose and throat
- Pale, boggy nasal mucosa with hypertrophic turbinates
- Nasal polyps are seen in 25–30% of patients with chronic allergic rhinitis. [8]
- Cobblestone appearance of the posterior pharyngeal wall
- Allergic shiners: hyperpigmentation and edema of the lower eyelid as a result of venous congestion
- Allergic salute: a habit of wiping the nose with a transverse or upward movement of the hand
- Allergic nasal crease: a transverse hyperpigmented or hypopigmented line that is seen at the junction of the lower third and the middle third of the nasal bridge, which is the natural crease formed when the nose is pushed upwards by the allergic salute
- Adenoid facies
- Chronic allergic rhinitis can predispose the patient to recurrent sinusitis and/or otitis media.
Hypertrophic turbinates are pink or violaceous, hard, sensitive to probing, immobile, and shrink with nasal decongestant therapy. Nasal polyps are pale, soft, mobile, insensitive, and do not decrease in size following therapy with nasal decongestants.
Classification
Classification on the basis of a temporal pattern of allergen exposure may help identify the causative antigen. Classification based on the frequency and duration of symptoms is useful for guiding treatment. [4][9]
| Clinical classification of allergic rhinitis [4][5] | ||
|---|---|---|
| Classification criteria | Definition | |
| Temporal pattern of allergen exposure | Episodic allergic rhinitis | Symptoms occur on exposure to allergens that are not normally a part of the individual's environment. |
| Seasonal allergic rhinitis | Symptoms occur on exposure to allergens that occur during particular seasons. | |
| Perennial allergic rhinitis | Symptoms occur on exposure to allergens that are normally a part of the patient's environment. | |
| Frequency | Intermittent allergic rhinitis | Duration of symptoms: < 4 days/week or < 4 weeks/year |
| Persistent allergic rhinitis | Duration of symptoms: > 4 days/week for > 4 weeks/year | |
| Severity | Mild allergic rhinitis | Symptoms do not interfere with the quality of life. |
| Moderate to severe allergic rhinitis | Symptoms interfere with the quality of life. | |
Diagnostics
Approach [1][5]
- Obtain a detailed clinical history identifying:
- Clinical features of allergic rhinitis
- Allergen exposure
- Medication history
- Coexisting conditions (e.g., asthma, atopic dermatitis, otitis media)
- Order allergen testing:
- Additional diagnostic modalities (e.g., imaging and nasal endoscopy)
- Not routinely required
- Consider in cases of diagnostic uncertainty (e.g., to rule out sinonasal disorders). [1]
Allergic rhinitis is primarily a clinical diagnosis in patients presenting with characteristic clinical features (i.e., nasal congestion, rhinorrhea, itchy nose, sneezing) that are triggered by seasonal, perennial, or episodic exposure to allergens. [5]
Epistaxis, unilateral rhinorrhea or nasal blockage, severe headache, or anosmia are atypical for allergic rhinitis and should prompt further workup for an alternative diagnosis. [1]
Allergen testing [1][5]
Testing for aeroallergens is recommended in all patients with features consistent with allergic rhinitis. Testing for food allergens is not routinely recommended. [5]
Skin tests
- Indication: preferred over blood tests as they are more sensitive
-
Possible contraindications
- Concern for anaphylaxis with skin testing and/or patients at high risk if anaphylaxis develops
- Dermatological conditions that may interfere with the interpretation of skin test results
- Use of medications that cannot be interrupted and that can interfere with the response to skin testing
-
Options [10]
- Skin prick test: The development of a pruritic wheal at the site of the skin puncture (typically within 15–20 minutes) strongly suggests allergen sensitization.
- Intradermal test: Consider if there is a strong suspicion of allergen sensitization in patients with a negative skin prick test.
Skin tests to detect allergen sensitization can cause anaphylaxis! [1]
Blood tests
-
Indications
- Presence of contraindications for skin tests
- Patient preference
- Method: immunoassays to identifiy allergen-specific IgE in the serum (allergen-specific IgE test)
Blood tests for allergen sensitization are preferred if there is concern for anaphylaxis with skin testing, [1]
In asymptomatic individuals, a positive skin or blood test for a particular allergen is not diagnostic of an allergy to that allergen. [1]
Differential diagnoses
- Nonallergic rhinitis
- Sinusitis
- Other causes of nasal congestion (e.g., nasal polyps, adenoid hypertrophy)
The differential diagnoses listed here are not exhaustive.
Management
Approach [1][5]
- Recommend environmental modifications.
- Initiate pharmacotherapy with antihistamines (intranasal or oral) or intranasal corticosteroids.
- Assess response to therapy in 5–7 days.
- If symptoms are under control:
- Step down and stop pharmacotherapy if the trigger is no longer present.
- Or administer treatment on an as-needed basis.
- If symptoms are uncontrolled, consider any of the following :
- An alternative monotherapy
- Adding a symptom-specific agent to initial pharmacotherapy
- Referral for allergen immunotherapy
- If symptoms are under control:
Environmental modifications [1][5]
- Advise patients to avoid exposure to putative allergens (e.g., dust, animal dander, mold spores, plant pollen, or latex).
- Examples of environmental modifications include:
Pharmacotherapy [1][5]
Medications for allergic rhinitis can be initiated empirically. The choice of initial pharmacotherapy depends on the severity and type of allergic rhinitis and should be tailored to the clinical response (see “Approach” above).
- Episodic allergic rhinitis, intermittent seasonal allergic rhinitis, or perennial allergic rhinitis: : intranasal or oral second-generation antihistamines on an as-needed basis
-
Persistent allergic rhinitis
- Mild allergic rhinitis: monotherapy with intranasal corticosteroids (e.g., budesonide, fluticasone)
- Moderate to severe allergic rhinitis: intranasal corticosteroids, with or without intranasal antihistamines
- Select patients: : Consider adding symptom-specific agents (e.g., decongestants, anticholinergics) to intranasal corticosteroid and antihistamine therapy.
Intranasal steroids are considered the most effective maintenance treatment for persistent allergic rhinitis. Potential adverse effects include nosebleeds and, rarely, septal perforation with long-term use. [5]
In patients with severe or refractory allergic rhinitis, consider a 5–7 day course of oral corticosteroids and refer to an allergist. [5]
| Medications for allergic rhinitis [1][3][5] | ||
|---|---|---|
| Drug class | Examples | Clinical considerations |
| Intranasal corticosteroids |
| |
| Antihistamines |
|
|
| Decongestants (α1-sympathomimetics) |
|
|
| Mast cell stabilizers |
|
|
| Anticholinergics |
|
|
| Leukotriene receptor antagonists |
| |
Intranasal sympathomimetics should generally not be used for more than 3–5 days because of the risk of rebound nasal congestion (rhinitis medicamentosa). [1][5]
Montelukast is associated with a risk of serious psychiatric events including suicide and may only be used in patients with concomitant asthma using a shared decision-making strategy.
Allergen immunotherapy [1][5]
- Controlled exposure to gradually increasing doses of the allergen (sublingually or subcutaneously) in order to reduce sensitivity to the allergen [11]
- Consider in patients with allergen-specific IgE antibodies and any of the following: [5]
- Inadequate symptom control with pharmacotherapy with/without environmental modifications
- Preference for immunotherapy over other treatment methods after a shared decision-making conversation
- Concomitant asthma
- Generally requires ≥ 3 years of treatment
Surgery [1][5]
- Indications: significant nasal obstruction in patients with treatment-resistant allergic rhinitis
- Procedure: reduction of hypertrophic nasal turbinates
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