Why has the incidence of allergies been increasing rapidly since the 1960's?
Better hygiene, less exposure to environmental antigens, diet is becoming more processsed
What are risk factors for allergy?
Alterations in exposure to: Infectious diseases during early childhood, environmental polution, allergen levels, dietary changes
What is allergy involving the a) skin, b) Upper respiratory, c) Lower respiratory, d) systemic
referred to as ?
A) Urticaria / angioedema
What is allergic rhinitis associated with?
What are symptoms of allergic rhinitis?
Immediate : sneezing, itch, nasal blockage, rhinorrhoea (a condition where the nasal cavity is filled with a significant amount of mucus fluid)
Late : chronic obstruction, hyposmia, hyperreactivity
What is an allergen?
antigen that causes allergic reactions
Usually a protein
What type of hypersensitivity reaction is allergy?
What is the process of an allergic reaction?
- Plasma cells produce IgE
- Bind to mast cells
Re - exposure:
Mast cells degranulate
Release histamine, leukotrines, prostaglandins and chemotactic factors
What is the result in mast cell degranulation?
Exaggerated response that causes damage to the host
Release of Histamine, leukotrienes, prostaglandins, chemotactic agents.
This has the effect of vasodilation, vascular permeability, smooth muscle contraction, leukocyte infiltration especially eosinophils
What is the acute phase and the late phase response of allergy?
Degranulation of mast cells, release of histamines, cytokines, leukotrines, interleukins, prostaglandins - systemic effects such as vasodilation, mucus secretions, nerve stimulation and smooth muscle contraction
Late phase response:
Due to migration of other leukocytes such as neutrophils, lymphocytes, eosinophils and macrophages to the initial site.
What is allergic rhinitis?
Allergic inflammation of the nasal airways
Occurs when the allergen is inhaled by an individual with a sensitized immune system
What does ARIA stand for?
Allergic rhinitis and its Impact on Asthma
What makes up intermittent / persistent classification of allergic rhinitis?
Intermittent = less than 4 days per week or less than 4 consecutive days
Persistent = Over 4 days per week and more than 4 consecutive days
What is the classification for mild allergic rhinitis?
No impairment of daily activities, sport, leisure
No impairment of work and school
Symptoms present but not troublesome
What is the classification of moderate - severe allergic rhinitis?
Impairment of daily activities, sport and leisure
Impairment of work / school
What is the diagnosis of allergic rhinitis?
RAST (Radioallergosorbent testing (RAST) detects allergen specific IgE in the blood. They are used when skin prick tests (the preferred allergy test) is not suitable or not available)
What are other allergy investigations?
Total serum IgE
Nasal allergen Challenge
What is the treatment of allergic rhinitis?
- Topical intranasal steroids
- Systemic steroids
- Sodium cromoglycate (a synthetic non-steroidal anti-inflammatory drug, inhaled to prevent asthmatic attacks and allergic reactions.)
- Allergen immunotherapy
- Anti - IgE
What is the treatment for mild intermittent symptoms of allergic rhinitis?
Oral H1 blocker
Intranasal H1 blocker and/or decongestant
What is treatment for moderate severe intermittent symptoms / mild symptoms of persistent allergic rhinitis?
Oral H1 receptor blocker
Intranasal H1 blocker and/or nasal decongestant
OR intranasal Corticosteroid
In persistent rhinitis review the patient after 2 - 4 weeks
If failure step up
If imporved - continue for one month
What is the treatment for moderate - severe persistent rhinitis?
H1 blocker / LTRA
Review after 2 - 4 weeks
If improved - step down and continue treatment for one month
Failure - review diagnosis, review compliance, look for infections or other causes
Add or increase intranasal CS dose
Rhinorrhea - add ipratropium
Bockage - Decongestant or oral corticosteroid (short term)
Failure - refer to specialist