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Allergic rhinitis - Coggle Diagram

- - - - House dust mites
      - These feed on shed human skin flakes which are particularly abundant in mattresses, bed bases, pillows, carpets, upholstered furniture, and furry toys.
      - Their growth is maximal at temperatures above 20°C and when humidity is above 80%. When humidity falls below 50%, they die.
      - They are present all year-round, but their numbers tend to peak in the spring and autumn.
      - Grass, tree, and weed pollens
        
        The length, duration, and intensity of the pollinating season varies from year to year, which can complicate identification of the responsible allergen.
        
        Trees generally pollinate in the spring.
        
        Grasses pollinate at the end of spring and beginning of summer.
        
        Weeds may pollinate from early spring to late autumn.
        
        Moulds
        
        Indoor moulds such as Alternaria, Cladosporium, and Aspergillus may be associated with damp environments.
        
        Animal dander
        
        Cat and dog hair are the most common animal allergens, which cause perennial symptoms.
        
        Less commonly, dander from horses, cattle, rabbits, and rodents (such as guinea pigs, hamsters, and rats) may cause allergic rhinitis.
        
        Occupational
        
        The incidence of allergic rhinitis is increased in certain occupations, such as working with 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.
- - - - A personal or family history of atopy (asthma, eczema, or allergic rhinitis). See the CKS topics on Asthma and Eczema - atopic for more information.
      - Symptoms which occur following exposure to a known causative allergen, such as:
      - Tree pollens — intermittent or chronic symptoms occur from early to late spring.
      - Grass pollens — intermittent or chronic symptoms occur from late spring to early summer.
      - Weed pollens — intermittent or chronic symptoms may occur from early spring to early autumn.
      - House dust mites — symptoms are worse on waking and are present all year-round, but may peak in autumn and spring.
        
        Animal dander — symptoms follow exposure to animal dander, and may be all year-round or occasional, depending on exposure.
        
        Occupational — intermittent or chronic symptoms tend to improve when the person is away from work, such as weekends and holidays.
- - - - Nasal intonation of the voice.
      - Darkened eye shadows under the lower eyelid due to chronic congestion (so-called 'allergic shiners').
      - Horizontal nasal crease across the dorsum of the nose (seen in severe rhinitis).
      - Deviated or perforated nasal septum; depressed or widened nasal bridge.
      - Nasal mucosa swelling and greyish discolouration (typically seen in allergic rhinitis); nasal polyps (rare in children); hypertrophic nasal turbinates (suggests inflammation); foreign bodies.
      - Purulent nasal discharge suggesting sinusitis. See the CKS topic on Sinusitis for more information.
      - Eye involvement suggesting allergic conjunctivitis. See the CKS topic on Conjunctivitis
- - - - Drugs
      - A number of drugs may cause or aggravate rhinitis symptoms, such as alpha-blockers, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, chlorpromazine, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and cocaine.
      - Rebound symptoms and a paradoxical increase in nasal congestion may occur when stopping prolonged treatment with intranasal decongestants due to rebound vasodilatation (so-called 'rhinitis medicamentosa'). See the section on Intranasal decongestants
      - Endocrine
        Hormonal rhinitis should be considered when symptoms coincide with pregnancy, starting the oral contraceptive pill, hormone replacement therapy (HRT), or hypothyroidism. See the CKS topics on Contraception - combined hormonal methods and Hypothyroidism for more information.
      - Food and drink
        
        Alcohol, sulphites, and spicy foods may cause rhinorrhoea and facial flushing.
        
        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.
        
        Systemic
        
        May be caused by primary defects in mucus production (for example, cystic fibrosis), primary ciliary dyskinesia (Kartagener syndrome), and granulomatous disease (for example, granulomatotis with polyangitis [previously known as Wegener's granulomatosis] and sarcoidosis).
        
        Structural
        
        Typically caused by deviated nasal septum, nasal polyps, hypertrophic turbinates, adenoidal hypertrophy, foreign body, or cerebrospinal fluid (CSF) leak (rare), for example.
        
        Sinonasal tumour (rare) should be excluded if there are unilateral symptoms, recurrent bloody nasal discharge or nosebleeds, nasal pain, anosmia, or visual disturbance.
- - - - For people with grass pollen allergy, advise to:
      - Avoid walking in grassy, open spaces, particularly during the early morning, early evening, and during mowing, when the pollen count is high.
      - Avoid drying washing outdoors when the pollen count is high.
      - Keep windows shut in cars and buildings.
      - Plan holidays to avoid the pollen season, where possible.
      - Shower or wash hair following high pollen exposures.
    - - For people with confirmed house dust mite allergy following allergy testing, advise to:
      - Not fit mattresses, pillows, and duvets with house dust mite impermeable covers.
      - Use synthetic pillows and acrylic duvets, and keep furry toys off the bed.
      - Wash all bedding and furry toys at least once a week at high temperatures.
      - Choose wooden or hard floor surfaces instead of carpets, if possible.
      - Fit blinds that can be wiped clean instead of curtains. Surfaces should be wiped regularly with a clean, damp cloth.
      - If the person has mild-to-moderate intermittent, or mild persistent symptoms:
        
        Advise on the 'as-needed' use of an intranasal antihistamine first-line, or a second-generation, non-sedating oral antihistamine, depending on the person's age and personal preference.
        
        Advise that intranasal antihistamines (azelastine) have a faster onset of action and are more effective than oral preparations. See the section on Intranasal antihistamines in Prescribing information for more information on intranasal antihistamines and intranasal spray and drop technique.
        
        Oral antihistamine options include loratadine or cetirizine, which may be available over-the-counter.
    - - If the person has moderate-to-severe persistent symptoms, or initial drug treatment is ineffective:
      - Prescribe a regular intranasal corticosteroid to be used during periods of allergen exposure.
      - Options include intranasal mometasone furoate, fluticasone furoate, or fluticasone propionate. See the CKS topic on Corticosteroids - topical (skin), nose, and eyes for more prescribing information including different preparations and advice on intranasal spray and drop technique.
      - Advise the person that the onset of action is 6–8 hours after the first dose, but the maximal effect may not be seen until after two weeks.
        
        Nasal drops may be preferred if there is severe nasal obstruction.
        
        Advise the person not to increase beyond the prescribed dose as there is no evidence of additional benefit, and do not switch to an alternative preparation, as they all have comparable efficacy.
        
        Consider arranging referral for specialist assessment and management to an allergy or ear, nose, and throat (ENT) specialist if:
        
        There are red flag features such as unilateral symptoms, blood-stained nasal discharge, recurrent epistaxis, or nasal pain — arrange an urgent two-week wait referral to ENT.
        
        There is predominant nasal obstruction and/or a structural abnormality such as deviated nasal septum which makes intranasal drug treatment difficult — arrange referral to ENT.
        
        There are persistent symptoms despite optimal management in primary care — consider referral to an allergy specialist for allergy testing and possible immunotherapy treatment, depending on local referral pathways and availability.