Hay fever

Allergic rhinitis may be:

• seasonal (also called "hay fever")
  • caused by grass and tree pollen allergens, symptoms typically observed during the same time each year
• perennial
  • caused by house dust mites and animals, symptoms occur right throughout the year
• occupational
  • caused by allergens at the workplace e.g., flour allergy in a baker (1)

Allergic rhinitis can also be divided according to the severity and persistence of symptoms:

• mild intermittent
• moderate severe intermittent
• mild persistent
• moderate severe persistent (1)

It is characterised by:

• rhinorrhoea
• nasal blockage
• sneezing attacks for longer than 1 hour per day lasting longer than 2 weeks
• itching—eyes, nose
• watery eyes
• interference with sleep leading to daytime sleepiness (2)
• malaise
• headache (3)
• wheezing
• shortness of breath (4)

Allergic rhinitis may coexist with asthma, eczema and chronic sinusitis. It occurs when an individual, previously exposed to an antigen, has made IgE antibodies to that antigen. The IgE is incorporated into the cell membranes of mast cells, and upon subsequent exposure to that antigen, the mast cells degranulate, releasing inflammatory mediators such as histamine and slow reacting substance of anaphylaxis (SRS-A) (1).

A review (151 studies; most unclear/high risk of bias) found azelastine-fluticasone, fluticasone furoate & fluticasone propionate had highest probability of resulting in moderate or large improvements in Total Nasal Symptom Score & Rhinoconjunctivitis Quality-of-Life Questionnaire (5).

References:

1. Clinical knowledge summaries, safe practical clinical answers. Allergic rhinitis.
2. Hoyte FCL, Nelson HS. Recent advances in allergic rhinitis. F1000Res. 2018;7: F1000 Faculty Rev-1333; published online 2018 Aug 23.
3. Quillen D, Feller DB. Diagnosing rhinitis: allergic vs. nonallergic. Am Fam Physician 2006;73(9):1583–1590.
4. MeReC bulletin (2004);14(5):17–20.
5. Sousa-Pinto B et al. Intranasal antihistamines and corticosteroids in allergic rhinitis: A systematic review and meta-analysis. J Allergy Clin Immunol. 2024 Apr 27:S0091-6749(24)00419-6.