Definition

IgE-mediated inflammatory disorder of the nose which occurs when the nasal mucosa becomes exposed and sensitised to allergens.

Environmental Allergens

1. House dust mites (continuous)

2. Pollen: grass (spring/summer), tree (spring), and weed (autumn) pollens

3. Moulds (indoor, damp indoor environment)

4. Animal dander (continuous) : cat and dog hair; dander from rabbits, and rodents (such as guinea pigs, hamsters, and rats)

5. Occupational such as latex gloves, chlorine, flour, wood dust, or laboratory animals.
   Typically, there is a defined latency period of months to years, during which sensitization to a causal agent occurs.

Classification

Seasonal seasonal variation e.g. grass (summer) and tree (spring) pollen allergens (—> 'hay fever')

Perennial continuous symptoms e.g. house dust mites and animal dander

Occupational symptoms due to exposure to allergens in the work environment, for example, flour allergy in a baker.

Prevalence

Allergic rhinitis is common and its prevalence is increasing in the UK.

Complications

• Asthma (bronchial hyper-reactivity may be induced by upper airway inflammation)

• Sinusitis

• Nasal polyps

• Oral allergy syndrome (pollen-food syndrome) — symptoms of oral itching and swelling occur due to cross-reactivity between aeroallergens, such as birch pollen, and vegetables and fruits such as apples

Diagnosis

Classic symptoms which occur following exposure to a known causative allergen.

Nasal symptoms
sneezing, nasal itching, nasal discharge (rhinorrhoea), and nasal congestion
bilateral symptoms typically develop within minutes following allergen exposure.
Also, postnasal drip, itching of the palate, and cough; chronic nasal congestion (snoring, mouth breathing, and halitosis).

Allergic conjunctivitis
Bilateral itching, redness, and tearing

A personal or family history of atopy
Asthma
Eczema

Assessment

• The type, frequency, persistence, and location of symptoms.

• The severity and impact of symptoms.

• Housing conditions, pets, and occupation.

• Any drugs that may cause or aggravate symptoms.

• Any family history of atopy.

• Examination for signs and underlying causes of rhinitis, and/or associated conditions.

Differential diagnosis

Infective rhinitis

There is an acute onset of symptoms of one week or less, with typical features of an associated viral upper respiratory tract infection, such as cough, fever, or lymphadenopathy.
If nasal discharge is clear, infection is less likely.

Non-allergic rhinitis

1. Autonomic or irritant rhinitis
   Physical exposure (changes in temperature or humidity, or with exercise) or chemical irritant exposure (volatile chemicals such as perfumes, tobacco smoke, and odours).
   Non-IgE mediated pathway.

2. Drugs
   Alpha-blockers, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, chlorpromazine, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and cocaine.
   Rebound symptoms when stopping prolonged treatment with intranasal decongestants due to rebound vasodilatation (so-called 'rhinitis medicamentosa').

3. Endocrine
   Pregnancy, starting the oral contraceptive pill, hormone replacement therapy (HRT), or hypothyroidism.

4. Non-allergic rhinitis with eosinophilia syndrome (NARES)
   This rare condition is a diagnosis of exclusion characterized by nasal eosinophils in people with perennial symptoms, and occasionally reduced sense of smell.
   50% of people develop aspirin-sensitive disease with asthma and nasal polyposis later in life.

5. Systemic
   Primary defects in mucus production (cystic fibrosis),
   Primary ciliary dyskinesia (Kartagener syndrome)
   Granulomatous disease (for example, Wegener's granulomatosis and sarcoidosis).

6. Structural
   Nasal septum, nasal polyps, hypertrophic turbinates, adenoidal hypertrophy, foreign body, or cerebrospinal fluid (CSF) leak (rare), for example.

7. Sinonasal tumour (rare) should be excluded if there are
   Unilateral symptoms, recurrent bloody nasal discharge or nosebleeds, nasal pain, anosmia, or visual disturbance.

Management

Nasal spray technique

• Shake the container well and look down.

• Using the right hand for the left nostril, put the nozzle just inside the nose aiming for the outside wall.

• Squeeze once or twice in different directions, while breathing in gently through the nose. Do not sniff.

• Change hands, then repeat for the other nostril.

Nasal drop technique

• Gently blow the nose to try and clear it.

• Shake the container well.

• Tilt the head backwards.

• Place the drops in the nostril (squeeze the container gently if necessary).

• Keep the head tilted and sniff gently to let the drops penetrate.

• Repeat for the other nostril, if required.

Mild-to-moderate intermittent, or mild persistent symptoms

1. Nasal irrigation with saline.

2. As-needed
   intranasal antihistamine azelastine
   non-sedating oral antihistamine (second-generation) cetirizine, loratadine
   intranasal chromone sodium cromoglicate

   Ensure correct nasal spray and drop technique

3. Allergen avoidance techniques if there is a specific identified causative allergen following ALLERGY TESTING

Moderate-to-severe persistent symptoms

Regular intranasal corticosteroid during periods of allergen exposure
mometasone furoate, fluticasone furoate, or fluticasone propionate

Advise the person to be reviewed after 2–4 weeks 

if symptoms persist after initial treatment, as management may need to be stepped up

Refractory allergic rhinitis

Add-on treatments
intranasal decongestant ephedrine or xylometazoline (maximum 5-7 days)
intranasal anticholinergic for watery rhinorrhoea, ipratropium bromide
combination intranasal antihistamine and corticosteroid Dymista® spray combines intranasal antihistamine (azelastine) and intranasal corticosteroid (fluticasone propionate)
leukotriene receptor antagonist 10 mg once daily, dose to be taken in the evening.

A short course of oral corticosteroid for severe, uncontrolled symptoms that are significantly affecting quality of life.

• For adults — prednisolone 0.5 mg/kg in the morning for 5–10 days.

• For children — prednisolone 10–15 mg in the morning for 3–7 days.

Referral to ENT

1. There are red flag features suggesting an alternative or serious diagnosis.
   unilateral symptoms, blood-stained nasal discharge, recurrent epistaxis, or nasal pain — arrange an urgent two-week wait referral to ENT.

2. There are persistent symptoms despite optimal management in primary care.

3. Allergen avoidance techniques such as house dust mite or animal dander avoidance are being considered, as allergy testing may be needed.

4. The diagnosis is uncertain, as allergy testing may be needed.

Allergy Testing +/- immunotherapy treatment

Depends on local referral pathways and availability.

Options include:

Skin prick testing: high negative predictive value. It has a better positive predictive value than RAST

Serum-specific immunoglobulin (Ig) E to allergens such as house dust mites, pollen, and animal dander (radioallergosorbent test [RAST]).

Immunotherapy treatment

Suitable option if predominantly due to one allergen such as grass pollen or house dust mite.

Treatment may be by subcutaneous injection or sublingual, and involves exposing the person to increasing amounts of allergen to induce clinical and immunological tolerance.

• Subcutaneous therapy may involve weekly initial dosing regimens followed by 4–6 weekly maintenance injections usually for 3 years.
  Pre-seasonal immunotherapy may be effective for pollen allergy.

• Sublingual immunotherapy may be an alternative for the treatment of allergic rhinitis due to one or more species of grass pollen and house dust mite.
  If tolerated, subsequent doses may be self-administered daily at home for, usually 3 years.