Allergic Rhinitis Lecture PDF

Allergic rhinitis (AR) Dr. Sara Youssif Ibrahim MSc,PhD, BCPS At the end of this lecture, you will be able to: Know what is allergic rhinitis. Define what common cause of allergic rhinitis. Identify Pathogenic mechanisms of allergic rhinitis. Know classification of allergic rhi...

Allergic rhinitis (AR) Dr. Sara Youssif Ibrahim MSc,PhD, BCPS At the end of this lecture, you will be able to: Know what is allergic rhinitis. Define what common cause of allergic rhinitis. Identify Pathogenic mechanisms of allergic rhinitis. Know classification of allergic rhinitis. Define how to manage allergic rhinitis. Define trigger points indicative for referral. Definition and forms of allergic rhinitis  Allergic rhinitis (AR) is an inflammatory process of the nasal mucosa, typically IgE-mediated, elicited by environmental allergens and characterized by the presence of inflammatory cells within the mucosa and submucosa.  The symptoms include nasal discharge, nasal itching, sneezing and nasal obstruction.  The course of the disease involves one or more of the symptoms, persisting for at least one hour a day for at least two consecutive days, which are reversible spontaneously or with treatment.  The disease is a serious public health problem in a number of countries, Allergic rhinitis has a profound negative impact on the quality of life of patients and their families (in the case of children with AR).  It is also a major cause of school and work absenteeism.  Consequently, it is vital to ensure timely and correct diagnosis, and implement appropriate management based on the latest international or national guidelines.  The current classifications of AR take into account the following criteria: 1) Allergen causing symptoms. 2) Duration of symptoms. 3) Severity of clinical symptoms reported by the patient, including AR-related quality of life. 4) Disease pathophysiology. Classifications of AR according to etiology 1) Seasonal allergic rhinitis (hay fever). 2) Perennial allergic rhinitis. 3) Episodic allergic rhinitis (EAR).  1) Seasonal allergic rhinitis (hay fever)  Seasonal allergic rhinitis (hay fever) affects 10–15% of population, and millions of patients rely on OTC medicines for treatment.  The symptoms of allergic rhinitis occur after an inflammatory response involving the release of histamine, which is initiated by allergens being deposited on the nasal mucosa.  Allergens responsible for seasonal allergic rhinitis include grass pollens, tree pollens and fungal mold spores.  2) Perennial allergic rhinitis  Perennial allergic rhinitis occurs when symptoms are present all year round and is commonly caused by the house dust mite, animal dander and feathers.  Some patients may suffer from perennial rhinitis, which becomes worse in the winter months.  3) Episodic allergic rhinitis (EAR)  is caused by exposure to a specific airborne allergen on a sporadic and short-term basis.  such as visiting a house with pets. Classifications of AR according to duration  AR is classified into intermittent (INT) and persistent (PER) types. 1. Intermittent allergic rhinitis is defined by symptom duration of less than 4 days per week or less than a month per year. 2. PER allergic rhinitis refers to the presence of symptoms for ≥ 4 days per week and ≥ 1 month per year.  Classifications of AR according to duration  AR is classified as either mild or moderate/severe depending on the impact of the disease on the following quality-of-life measures: a) Daily activities and sport. b) School/work attendance. c) Sleep. d) Need of therapy, as reported by the patient.  Classifications of AR according to duration  In mild AR, there is NO impact on the quality- of-life aspects listed above.  In moderate /severe AR, an adverse effect on one or more of the above items is present.  Pathogenic mechanisms of allergic rhinitis  There are various causes for allergic rhinitis sensitization, but their mechanisms remain largely unknown.  Genetic factors and IgE antibody production are the most important. Pathogenic mechanisms of allergic rhinitis When a bit of pollen enters the nose. It can get picked up by a dendritic cell which is a type of immune cell that gobbles up foreign particles and presents it to a nearby lymphocyte called a T cell. If the T cell gets activated, it produce cytokines which helps to get other immune cells involved. There are too many T cells that, when activated, stimulate B cells, another group of lymphocytes, to produce IgE antibodies. Those IgE antibodies get released into the bloodstream and bind to mast cells, which are immune cells in the tissue that carry within themselves a load histamine, prostaglandin D2, kinin, and leukotriene. Pathogenic mechanisms of allergic rhinitis Once bound by IgE the mast cells are “primed”, meaning if pollen enters the body again in the future, those mast cells degranulate and release their histamine into the local tissue. The histamine causes blood capillaries to dilate and become leaky which brings more fluid and immune cells to the area where the mast cells are located. These irritate the sensory nerve endings and blood vessels of the nasal mucosa to cause sneezing, watery rhinorrhea, and nasal mucosal swelling (nasal blockage). Because the eyes and nose are portals of entry for infections, there are lots of mast cells around those areas for extra protection. Symptoms  1. Sneezing  Sneezing is caused by histamine irritation of the sensory nerve (trigeminal nerve) in the nasal mucosa, transmitted to the sneezing center of the medulla oblongata.  The irritant effects of histamine on the sensory nerve are enhanced by allergies to cause sneezing.  2. Watery rhinorrhea  The sensory nerve irritation in the nasal mucosa causes sneezing reflex.  Most rhinorrhea is secreted from the nasal glands.  3.Nasal mucosal swelling Nasal mucosal swelling is caused by interstitial edema in the nasal mucosa, due to plasma leakage, and congestion of the nasal mucosal vessels. Leukotrienes released from infiltrating inflammatory cells, particularly eosinophils, play a major role in nasal mucosal swelling. Continuous antigen irritation cause chronic lesions.  Diagnosis of allergic rhinitis A definite diagnosis is made based on: 1) three symptoms (sneezing and nasal itching, watery rhinorrhea, and blocked nose). 2) Positive nasal eosinophil tests in the season. 3) Identified causative allergens, based on skin reactions or serum allergen-specific IgE antibody measurements. Treatment Improvement in symptoms Timescale should occur within a few days. If no improvement is noted after 5 days, the patient might be referred to the doctor for other therapy.  Aim of treatment  The aim of treatment is to alleviate symptoms and remove difficulties with everyday life.  Choose a treatment based on severity, disease type, and lifestyle. Management  Non-pharmacological treatment Natural courses and communication with patients 1. Combinations of pharmacotherapies based on severity and disease types and communication with patients improve patients' satisfaction and quality of life. 2. Elimination and avoidance of antigens. 3. In addition to the cleaning, lowering humidity with dehumidifier is effective in reducing mites. 4. For pet allergy, avoid contact with causative pets and keep dogs and cats clean.  Pharmacological management  Management is based on whether symptoms are intermittent or persistent and mild or moderate.  Options include antihistamines, nasal steroids and sodium Cromoglycate in formulations for the nose and eyes.  OTC antihistamines and steroid nasal sprays are effective in the treatment of allergic rhinitis.  The choice of treatment should be rational and based on the patient’s symptoms and previous history.  Many cases of hay fever can be managed with OTC treatment and it is reasonable for the pharmacist to recommend treatment.  Patients with symptoms that do not respond to OTC products can be referred to the doctor at a later stage.  1. Antihistamines  Many pharmacists would consider these drugs to be the first-line treatment for mild to moderate and intermittent symptoms of allergic rhinitis.  They are effective in reducing sneezing and rhinorrhea, less so in reducing nasal congestion.  Non-sedating antihistamines available OTC include acrivastine, cetirizine and Loratidine.  All are effective in reducing the symptoms of hay fever and have the advantage of causing less sedation than some of the older antihistamines.  (1) First-generation antihistamine First-generation antihistamine often cause adverse effects, such as sleepiness, impaired performance, and dry mouth, but have immediate effects on sneezing and watery rhinorrhea. They are contraindicated for patients with glaucoma, prostatic hyperplasia, and asthma because of their potent anticholinergic effects. e.g. (chlorpheniramine & diphenhydramine).  (2) Second-generation antihistamine Cetirizine and Loratidine are taken once daily, while acrivastine is taken three times daily. For OTC Loratidine can be recommended for children over 2 years, cetirizine over 6 years and acrivastine over 12 years. While drowsiness is an unlikely side-effect of any of the three drugs, patients might be well advised to try the treatment for a day before driving or operating machinery. Loratidine may be less likely to have any sedative effect than the other two, but the incidence of drowsiness is extremely small.  Topical antihistamines Nasal treatments Azelastine is a nasal spray used in allergic rhinitis. treatment should begin 2–3 weeks before the start of the hay fever season. Its place in treatment is likely to be for mild and intermittent symptoms in adults and children over 5 years. Educate the patient to keep the head upright during use to prevent the liquid entering into the throat and causing an unpleasant taste.  2. Decongestants Oral or topical decongestants may be used short term to reduce nasal congestion alone or in combination with an antihistamine. Topical decongestants can cause rebound congestion, especially with prolonged use. They shouldn’t be used for more than one week.  2. Decongestants Oral decongestants are occasionally included such as pseudoephedrine. Their use, interactions and adverse effects are considered in the lecture of ‘Cold and flu’.  2. Decongestants Eye drops containing an antihistamine and decongestant combination are available and may be of beneficial in eye symptoms, particularly when symptoms are intermittent. The sympathomimetic acts as a vasoconstrictor, reducing irritation and redness. Eye drops that contain a decongestant should not be used in patients who have glaucoma or who wear soft contact lenses.  3.Steroid nasal sprays Beclometasone nasal spray and fluticasone metered nasal spray can be used for the treatment of seasonal allergic rhinitis. A steroid nasal spray is the treatment of choice for moderate to severe nasal symptoms that are continuous. The steroid acts to reduce inflammation that has occurred as a result of the allergen’s action.  3.Steroid nasal sprays Regular use is essential for full benefit to be obtained and treatment should be continued throughout the hay fever season. Dryness and irritation of the nose and throat as well as nose bleeds have occasionally been reported; otherwise side- effects are rare. Beclometasone and fluticasone nasal sprays can be used in patients over 18 years of age for up to 3 months.  3.Steroid nasal sprays They should not be recommended for pregnant women or for anyone with glaucoma. Patients are sometimes alarmed by the term ‘steroid’, associating it with potent oral steroids and possible side-effects. Therefore, the pharmacist needs to take account of these concerns in explanations about the drug and how it works.  1.Potent effects 2. Relatively rapid effects Characteristics 2. Few adverse effects of nasal steroids. 3.Effective equally to the 3 symptoms of nasal allergy 4. Effective only at administration site  4. Mast cell stabilizer Since the development of disodium Cromoglycate (DSCG), local agents (eye drops and nasal spray) and oral agents, such as tranilast, amlexanox, and pemirolast potassium, have been on the market. To achieve sufficient clinical effects, 2- week prolonged administration is required. Improvement rates are increased by continuous administration. Adverse effects, such as sleepiness and dry mouth, do not occur.  4. Mast cell stabilizer (Sodium Cromoglycate) Sodium Cromoglycate is available OTC as nasal drops or sprays and as eye drops. Cromoglycate can be effective as a prophylactic if used correctly. It should be started at least 1 week before the hay fever season is likely to begin and then used continuously. There is no significant side-effects, although nasal irritation may occasionally occur. 4. Sodium Cromoglycate Cromoglycate eye drops are effective for the treatment of eye symptoms that are not controlled by antihistamines. Cromoglycate should be used continuously to obtain full benefit. The eye drops should be used four times a day. The eye drops contain the preservative benzalkonium chloride and should not be used by wearers of soft contact lenses.  Car windows and air vents should be kept closed while driving. Otherwise a high pollen Further advice concentration inside the car can result. Where house dust mite is identified as a problem, regular cleaning of the house to maintain dust levels at a minimum can help.  Wheezing and shortness of breath When Tightness of chest to Painful ear refer Painful sinuses Purulent conjunctivitis Failed medication  Time to think??? 1- what are the common causes of allergic rhinitis? 2- How to manage allergic rhinitis? 3- What are trigger points indicative for referral in allergic rhinitis? Thank You