allergic rhinitis (hay fever, ragwood allergy)

Etiology

• IgE-mediated hypersensitivity to nasally-inhaled allergens
• seasonal allergens
  • ragweed: mid August until 1st frost*
  • tree pollen: March to May
  • grass pollen: May to July
• perennial allergens
  • dust mites
  • molds
  • animal dander or saliva*
  • cockroach antigen
• see 'allergens causing allergic rhinitis'

* seasonal allergic rhinitis & allergic conjunctivitis in late summer & early fall are most likely to be caused by weed pollen even in pet owners with dogs or cats

Epidemiology

• 15-30% of U.S. population
• may be seasonal or perennial

Pathology

• IgE-mediated reactions against inhaled allergens
• irritation & inflammation of the nasal mucous membranes driven by type 2 helper T (Th2) cells
  • eyes & upper respiratory tract may also be involved
• generally requires about 3 seasonal exposures for a patient to develop clinically significant symptoms to a new aeroallergen
• nasal polyps may cause refractory nasal obstruction

Genetics

• defects in IL13 may be a cause of susceptibility to allergic rhinitis
• implicated genes: SDAD1, FOXJ1

Clinical manifestations

• sneezing
• rhinorrhea (thin, clear nasal discharge)
• postnasal drip
  • erythematous, sore throat
  • inflamed tonsils
• nasal congestion
  • pale, swollen nasal mucosa
  • turbinate edema
  • may lead to loss of taste &/or smell
  • may lead to sinusitis, acute or chronic
• allergic conjunctivitis often accompanies allergic rhinitis
• cough
• pruritus
• frequent nose rubbing (allergic salute)
• dry mouth
• halitosis
• fatigue
• sleep disturbances
• dark circles under the eyes (allergic shiners)

Laboratory

• nasal cytology (smears) may show eosinophils
• skin testing for allergen-specific IgE (preferred testing method)
• radioallergosorbent [RAST] testing

* clinical diagnosis

Radiology

• computed tomography of paranasal sinuses

* clinical diagnosis

Complications

• bronchitis
• asthma (coexisting asthma not uncommon)
• pollen-food allergy syndrome

Differential diagnosis

• infectious agents
  • viral, bacterial or fungal rhinitis
  • sinusitis
• non-infectious
  • vasomotor rhinitis
    • smoke
    • air pollution
    • perfumes
    • detergents & soaps
    • solvents or fumes
    • changes in temperature, light, or atmospheric pressure
    • emotion
    • not seasonal, negative skin testing
  • rhinitis medicamentosa
    • sympathomimetic nasal drops or sprays
    • cocaine
    • antihypertensives
      • reserpine
      • guanethidine
      • hydralazine
    • oral contraceptives
    • antidepressants
  • nasal obstruction
    • nasal polyps
      • asthma, aspirin intolerance -> nasal polyps with asthma
    • deviated nasal septum
    • nasal neoplasm
    • foreign body
    • hypertrophic turbinates or adenoids
  • systemic disorders
    • rhinitis of pregnancy
    • hypothyroidism
    • Wegener's granulomatosis
    • sarcoidosis
    • ciliary - cystic fibrosis
    • Sjogren syndrome
  • cerebrospinal fluid leak (CSF rhinorrhea)
  • atrophy of nasal mucosa

Management

• also see allergic rhinoconjunctivitis
• avoidance of allergen
• intranasal glucocorticoids (most effective agents)
  • also reduces ocular symptoms of allergic conjunctivitis
  • intranasal glucocorticoids
    • beclomethasone (Beconase, Vancenase)
      • 1 spray (42 ug) BID-QID
    • flunisolide (Nasalide) - 2 sprays (50 ug) BID
    • triamcinolone (Nasocort) - 2 sprays (110 ug) QD
    • budesonide
  • monotherapy with intranasal glucocorticoids initial treatment
  • as-needed intranasal glucocorticoids might not be quite as good as daily, but glucocorticoid exposure will be less
  • intranasal glucocorticoid plus antihistamine combination may be better than glucocorticoid alone
  • intranasal glucocorticoids do not improve asthma control
• antihistamines
  • azelastine (Astelin) 2 sprays/nostril BID (nasal spray)
    • intranasal antihistamine 1st add on treatment to intranasal glucocorticoid
  • loratadine (Claritin) 10 mg PO QD
  • fexofenadine (Allegra) 60 mg PO BID
  • astemizole (Hismanal) 10 mg PO QD
  • chlorpheniramine 4 mg PO TID/QID
• nasal ipratropium
• decongestants
  • effective but associated with rebound congestion (rhinitis medicamentosa)
  • pseudoephedrine (Sudafed) 30-60 mg QID
  • oxymetazoline (Afrin) intranasal enhances effectiveness of intranasal glucorticoids without rebound congestion
    • used alone may be associated with rhinitis medicamentosa
  • phenylephrine no better than placebo for nasal congestion
• montelukast (Singulair) 10 mg PO QD (adults)
  • NOT more effective than antihistamines or decongestants
  • NOT first line
• prednisone 40 mg PO QD for 5 days for very severe symptoms
• nasal chromolyn (Nasalchrom)
  • one spray (5.2 mg) TID/QID
  • prophylactic dosing
  • variable response
• tolerance induction (immunotherapy)
  • injection of allergen defined by RAST or skin testing
  • best response with seasonal allergies
  • patients with severe rhinitis not well controlled with intranasal glucocorticoids, antihistamines, decongestants
  • contraindicated with beta blocker therapy
    • systemic or ocular
    • increases likelihood of adverse systemic reaction
    • diminished response to epinephrine rescue
  • subcutaneous immunotherapy (SCIT) or 'allergy shots' may someday be replaced by daily sublingual-dissolving tablets that contain allergens
  • sublingual therapy for allergic rhinitis in U.S. limited to treatment of grass & ragweed allergy
• pregnancy
  • oxymetazoline nasal spray for 5 days
  • pseudoephedrine
  • intranasal cromolyn
  • intranasal beclomethasone
  • chlorpheniramine if unresponsive to cromolyn
  • treat sinusitis
• acupuncture of little of no benefit
• patient education
  • dust mites
    • keep humidity < 50%
    • wash sheets in hot water every week
    • encase mattress, boxspring & pillows in plastic
    • remove carpet, dust floors frequently
  • mold
    • keep humidity < 50%
    • vent bathrooms & clean with fungicidal agent
    • remove books & plants from the bedroom
    • install air filters
  • animal dander
    • remove pets from house
    • bathe pets frequently (at least every week)
    • shampoo carpets
  • pollen
    • avoid outdoors during pollen season
    • keep windows closed (use air conditioning)
    • install air filter units for air conditioning
• Refer to allergist if response to treatment is poor & diagnosis of allergic rhinitis seems probable
  • empiric treatment failure prior to referral
• Refer to ENT specialist if response to treatment is poor & diagnosis of allergic rhinitis is questionable.
• turbinate surgery is an option for patients refractory to medical therapy
  • improvement in congestion lasts at least one year

More general terms

• type 1 hypersensitivity; immediate hypersensitivity (allergy)
• rhinitis

More specific terms

• allergic rhinoconjunctivitis (hayfever)

Additional terms

• allergen skin testing
• allergens causing allergic rhinitis
• allergic conjunctivitis; Angelucci's syndrome
• radioallergosorbent [RAST] testing

Database

• OMIM: https://mirror.omim.org/entry/607154