Allergic Rhinitis and co-morbidities in children

Slides:



Advertisements
Similar presentations
ARIA QUIDELINES ON MANAGEMENT OF ALLERGIC RHINITIS
Advertisements

Introduction to ALLERGIES.
DR. SRINIVASAN. Goals of the lecture Definition of asthma & brief pathogenesis Initial diagnosis and ddx Factors that can trigger or aggrevate asthma.
Rhinosinusitis Sinusitis Sinusitis affects 31 million Americans annually. Chronic sinusitis is defined as unrelenting symptoms >12 weeks in duration.
Nursing Care of Clients with Upper Respiratory Disorders.
Copyright © 2013, 2010 by Saunders, an imprint of Elsevier Inc. Chapter 77 Drugs for Allergic Rhinitis, Cough, and Colds.
Management of Rhinitis in Patients with Asthma Michael Schatz, MD, MS Chief, Department of Allergy Kaiser Permanente, San Diego, CA.
C A SHINKWIN BON SECOURS GP STUDY DAY 28 JANUARY, 2012.
COUGH! QUESTIONS Worst complication of cough T or F: can usually find 1 etiology T or F: GERD almost always symptomatic(heartburn) BONUS.
Diseases and Disorders
นส. นุชนาถ ตั้งเวนิช เจริญสุข รหัส A chronic inflammatory disorder of the airway Airway hyperresponsiveness Recurrent episodes of wheezing,
Better Health. No Hassles. Hay Fever. Better Health. No Hassles. HAY FEVER Hay fever also called allergic rhinitis Unlike a cold, hay fever isn’t caused.
Dr muaid I. Aziz FIMCS.  Definition: its an inflammation of the lining of the nose characterized by two or more of the following symptoms nasal obstruction.
Allergy, Asthma and Immunotherapy Give Your Patients Back Their Lives S545v2.
BRONCHIAL ASTHMA DEFINITION Asthma is a chronic inflammatory lung disease characterized by  symptoms of cough, wheezing, dyspnoe and chest tightness.
Asthma What is Asthma ? V1.0 1997 Merck & ..
Disorders of the respiratory system. Respiratory structures such as the airways, alveoli and pleural membranes may all be affected by various disease.
BRONCHIAL ASTHMA YOUSEF ABDULLAH AL TURKI MBBS,DPHC,ABFM
Allergic Rhinitis Jillian La Monte RN.
Prepared by Dr. Muaid I.Aziz FICMS.  It’s a group of disorders characterized by inflammation of the mucosa of the nose & pns.
Allergic rhinitis in children Dr Gulamabbas Khakoo Consultant in Paediatrics, Hillingdon Hospital NHS Trust Consultant in Paediatric Allergy St Mary’s.
Objectives Upon completion of the lecture, students should be able to:  Define middle ear infection  Know the classification of otitis media (OM). 
Definitions  Middle ear is the area between the tympanic membrane and the inner ear including the Eustachian tube.  Otitis media (OM) is inflammation.
Immunology of Asthma Immunology Unit Department of Pathology King Saud University.
Immunology of Asthma Dr. Hend Alotaibi Assistant Professor & Consultant College of Medicine, King Saud University Dermatology Department /KKUH
Respiratory System PHARMACOLOGY
Bronchitis in children. Acute upper respiratory tract infections Prof. Pavlyshyn H.A., MD, PhD.
ALLERGIC RHNITIS - PREVALENCE n Affects million Americans n  10% - 30% of adults n  Up to 40% of children n  More common young boys n but little.
Allergic Rhinitis Richard Douglas. Prevalence Most common disease 20% adult population.
Diagnostic approach to the allergic patient. Allergic conditions in Israel.
Bronchial Asthma  Definition  Patho-physiology  Diagnosis  Management.
Asthma in children Dr Gulamabbas Khakoo BMBCh, FRCPCH
PEDIATRIC ASTHMA Anna M. Suray, M.D Respiratory Update Weirton Medical Center March 17, 2008.
Bronchial Asthma  Definition  Patho-physiology  Diagnosis  Management.
ALLERGOLOGY The branch of medical science that studies the causes and treatment of allergies.
1 Asthma October 30, Weiss, Gergen, & Hodgson (1992)2 Pediatric Statistics Prevalence increasing School absences Estimated as more than 10 million.
Rhinosinusitis Dr. Abdullah S. Al Yousef. Allergic Rhinitis Definition : An inflammatory disorder of the nose which occurs when the membranes lining the.
OBSTRUCTIVE SLEEP DISORDERS IN BREATHING IN CHILDHOOD Adenotonsillar Hypertrophy A. Kaditis, MD Pediatric Pulmonology Unit, Sleep Disorders Laboratory.
Component 1: Measures of Assessment and Monitoring n Two aspects: –Initial assessment and diagnosis of asthma –Periodic assessment and monitoring.
دکتر افشین شیرکانی فوق تخصص آسم و آلرژی و بیماری های نقص ایمنی استادیار دانشگاه عضو آکادمی آسم و آلرژی و ایمونولوژی آمریکا.
Upper Respiratory Tract Disorder Lecture 2 12/14/20151.
Rhinitis April 10, THE NOSE CT of THE NOSE.
ALLERGIC RHINITIS. Allergic rhinitis involves inflammation of the mucous membranes of the nose, eyes, eustachian tubes, middle ear, sinuses, and pharynx.
ASTHMA & OSAS Fulvio Braido Allergy and Respiratory Diseases Department University of Genoa Ostrutive Sleep Apnea Syndrome (OSAS) and Allergic Respiratory.
Allergic Rhinitis.
Clinical Practice Guideline in OME Otolaryngol Head Neck Surg May;130(5 Suppl):S
1 Robert J. Spiegel, M.D. Sr. V. P. Medical Affairs Chief Medical Officer Schering Plough FDA ADVISORY COMMITTEE 5/11/01.
Asthma in a Nutshell Holger Link, MD. The Complexity of Asthma Immune System Environment Injury and Repair Genes.
Daniel B. Jamieson, Elizabeth C. Matsui, Andrew Belli1, Meredith C. McCormack, Eric Peng Simon Pierre-Louis, Jean Curtin-Brosnan, Patrick N. Breysse, Gregory.
Joint Non-Prescription Drugs and Pediatric Advisory Committee Meeting October 18-19, 2007 Considerations for Extrapolation of Efficacy from Adults to Children.
 Mrs. Sabrina, age-35yrs from Gazipur developed running rose, red and itchy eye while she was working in the garden. Next day she developed chest tightness,
Asthma 1 د. ميريانا البيضة. DIAGNOSIS 2 3 Definition of asthma.
Allergology. Basic concepts n Allergy is an inappropriate and harmful response to normally harmless substance n Allergy is usually caused by proteins.
Dr Mazen Qusaibaty MD, DIS / Head Pulmonary and Internist Department Ibnalnafisse Hospital Ministry of Syrian health – Dr Mazen.
Allergic Reactions & Diseases BTE 303 Romana Siddique 1.
J R Hurst Thorax : Depart. Of Pulmonology R3 백승숙.
Asthma Review of Pathophysiology and Treatment. n definition of asthma –Asthma is a chronic inflammatory disorder of the airways in which many cells &
Diagnosis of asthma in adolescents and adults D.Anan Esmail Seminar Training Primary Care Asthma+ COPD
Immunology Unit Department of Pathology King Saud University
BRONCHIAL ASTHMA YOUSEF ABDULLAH AL TURKI MBBS,DPHC,ABFM
Drugs affecting the respiratory system
Bronchial Asthma Dr.Radhakrishna. S. A. Bronchial Asthma Dr.Radhakrishna. S. A.
Asthma Presented by Qassim j. odaa Master M.S.N..
Disorders of the respiratory system
Microbiology of Middle Ear Infections
E. SUTEDJA DERMATO – VENEROLOGICA DEPT. MEDICAL FACULTY UNPAD
Drugs Affecting the Respiratory System
Allergic Rhinitis allergic rhinitis inflammatory response release of histamine allergens (grass pollens,
Immunology Unit Department of Pathology King Saud University
Immunology Unit Department of Pathology King Saud University
Presentation transcript:

Allergic Rhinitis and co-morbidities in children Meenu Singh. MD, FCCP, FCIAAI Professor of Pediatrics, Advanced Pediatrics Centre, PGIMER, Chandigarh 160012.

Allergic Childhood Asthma Allergy can affect different children in different ways Food Allergy Atopic Dermatitis Atopic or Allergy March Natural sequence of allergic clinical conditions appearing during a certain age period and persisting over a number of years from childhood to adulthood Allergic Rhinitis Allergic Childhood Asthma Adult Asthma Atopy is the inherited tendency to develop harmful immune responses to harmless substances

Allergic Rhinitis Allergic rhinitis is clinically defined as a symptomatic disorder of the nose induced by an IgE-mediated inflammation after allergen exposure of the membranes lining the nose Most prevalent in Pediatric & Adolescent population Traditionally, classified into Seasonal allergic rhinitis (SAR) and Perennial allergic rhinitis (PAR)

Allergic Rhinitis: Classification Intermittent < 4 days per week or < 4 weeks Persistent > 4 days per week and > 4 weeks Mild Normal sleep No impairment of daily activities, sport, leisure Normal work & school No troublesome symptoms in untreated patients Moderate-Severe one or more items Abnormal sleep Impairment of daily activities, sport, leisure Abnormal work and school Troublesome symptoms J Allergy Clin Immunol 2001;108:S147-336.

Phases of allergy: PINE or MPI Chemotactic Factors Mast Cell

Allergic Rhinitis in children Pediatric rhinitis: Range of symptoms Cough Sneezing Nasal pruritus Nasal congestion Sore throats – recurrent infections Halitosis Respiratory distress – infant Hypernasality Behavioral problems Pediatric AR and its comorbid disorders Conjunctivitis Pharyngitis Sinusitis Asthma Eczema Otitis media Lymphoid hypertrophy/obstructive sleep apnea Speech impairment Failure to thrive Reduced quality of life Lack G. J Allergy Clin Immunol 2001;108:S9-15

AR in children: Clinical presentation Allergic rhinitis (AR) : Multiplicity of symptoms in the child Clinical presentation depends on the duration of allergen exposure (perennial versus seasonal and episodic exposure), age of the child, and extent of co-morbid disease. AR commonly presents in childhood as recurrent sore throats and upper respiratory tract infections Diagnosis of AR is often missed in children, who are thus treated inappropriately with multiple doses of antibiotics. Chronic cough is common symptom of AR or sinusitis in children resulting from postnasal drip and irritation of the larynx. In the minds of both patients and physicians, drowsiness has always been associated with medications that control allergic illnesses such as allergic rhinitis and allergic dermatoses. This is because the first generation antihistamines, which ruled the practice from 1950s to 1980s, invariably induced drowsiness. In addition, they had atropine-like action that was responsible for certain side effects. The second-generation antihistamines included astemizole, cetirizine and loratadine. These were free from atropine- like side effects. Further, their potential to cause sedation was also low. Terfenadine was the first of the second-generation antihistamines that was non-sedating. However, its use got curtailed because of some unforeseen adverse reactions: if given along with drugs such as erythromycin and ketoconazole, it could sometimes attain high plasma levels and produce serious cardiac dysrhythmias. So the search continued – for compounds that would be truly non-sedating and also devoid of any adverse effects on the heart. Allegra is the culmination of this quest and perhaps deserves the designation “third generation antihistamine” Lack G. J Allergy Clin Immunol 2001;108:S9-15 1

“The nose is the part of the lung which can be accessed by the finger” Allergic Rhinitis and Co-morbidities “The nose is the part of the lung which can be accessed by the finger”

Allergic Rhinitis and Co-morbidities How Common are the co-morbidities? Proportion of Allergic Rhinitis patients who also have selected co-morbid disorders Curr Med Res Opin 2004. 20:305-307

Co-morbidities and Allergic Rhinitis How Common is the association? Proportion of co-morbidities patients who also have Allergic Rhinitis Curr Med Res Opin 2004. 20:305-307

AR and Sinusitis in children AR and Sinusitis frequently co-exist and are definitely linked Sinusitis is one of the most underreported diagnoses in young children Pediatric sinus disease is characterized histologically by marked tissue eosinophilia, with mast cells expressing the activation marker There has been an  in association between AR, positive skin tests, and sinusitis In the minds of both patients and physicians, drowsiness has always been associated with medications that control allergic illnesses such as allergic rhinitis and allergic dermatoses. This is because the first generation antihistamines, which ruled the practice from 1950s to 1980s, invariably induced drowsiness. In addition, they had atropine-like action that was responsible for certain side effects. The second-generation antihistamines included astemizole, cetirizine and loratadine. These were free from atropine- like side effects. Further, their potential to cause sedation was also low. Terfenadine was the first of the second-generation antihistamines that was non-sedating. However, its use got curtailed because of some unforeseen adverse reactions: if given along with drugs such as erythromycin and ketoconazole, it could sometimes attain high plasma levels and produce serious cardiac dysrhythmias. So the search continued – for compounds that would be truly non-sedating and also devoid of any adverse effects on the heart. Allegra is the culmination of this quest and perhaps deserves the designation “third generation antihistamine” Lack G. J Allergy Clin Immunol 2001;108:S9-15 1

AR and Sinusitis: Pathophysiology Swelling of the mucous membranes, whether due to allergy, infection or other causes, may obstruct the drainage and aeration of the sinuses and one might therefore expect allergy to increase the risk of developing acute and chronic sinusitis.** During acute sinusitis there is swelling of mucous membranes, infiltration of eosinophils, and resulting ciliostasis and pooling of secretions that probably contribute to the subsequent infection Chronic rhino-sinusitis may be associated with a similar inflammatory process to that observed in AR In the minds of both patients and physicians, drowsiness has always been associated with medications that control allergic illnesses such as allergic rhinitis and allergic dermatoses. This is because the first generation antihistamines, which ruled the practice from 1950s to 1980s, invariably induced drowsiness. In addition, they had atropine-like action that was responsible for certain side effects. The second-generation antihistamines included astemizole, cetirizine and loratadine. These were free from atropine- like side effects. Further, their potential to cause sedation was also low. Terfenadine was the first of the second-generation antihistamines that was non-sedating. However, its use got curtailed because of some unforeseen adverse reactions: if given along with drugs such as erythromycin and ketoconazole, it could sometimes attain high plasma levels and produce serious cardiac dysrhythmias. So the search continued – for compounds that would be truly non-sedating and also devoid of any adverse effects on the heart. Allegra is the culmination of this quest and perhaps deserves the designation “third generation antihistamine” 1

AR and Sinusitis: Pathophysiology Frontal, Ethmoidal & Maxillary sinuses drain into middle meatus through an opening called ostium (osteomeatal complex) Allergic Rhinitis Nasal inflammation Viral URTI Mucosal swelling Obstruction of sinus passage Chronic Sinusitis Impedes normal movement of air and secretions Accumulation of thickened secretions & impaired ciliary movements Environment for infections

AR and Asthma in children Adolescent subjects with AR: 3-fold greater risk of developing de novo asthma as compared with subjects without AR Exposure to allergens and sensitization are important risk factors for childhood asthma AR and Asthma frequently co-exist and are considered as twin expressions of the same disease Possible relations exist between AR and asthma: AR may confound the diagnosis of asthma AR may be statistical associated with asthma AR may exacerbate coexisting asthma AR may have a causal role in the pathogenesis of asthma Lack G. J Allergy Clin Immunol 2001;108:S9-15

Cough Variant Rhinitis When Asthma & Rhinitis co-exists Children with chronic cough Cough-Variant Asthma Noctural cough in poorly controlled asthma No history of wheezing Responsive to brochodilator therapy Cough Variant Rhinitis Cough esp. nocturnal and post nasal drip Responsive to allergen avoidance; non-sedating long acting antihistamines; and/or intranasal steroids Misdiagnosis may lead to overtreatment inhaled steroids, 2 agonists and oral steroides When Asthma & Rhinitis co-exists Asthma may appear to be worse than it is Cough may be misattributed to asthma This may lead to over-treatment with high dose inhaled steroids Correct diagnosis and treatment of AR has a steroid sparing effect Lack G. J Allergy Clin Immunol 2001;108:S9-15

AR with Asthma: Pathophysiology Inflammation in the nose lower airway hyperresponsive. Possible mechanisms include Nasobronchial reflex: Nasal allergic response altering bronchial responsiveness through. Rhinovirus adhesion theory: Allergen induced ICAM-1 serves as receptor for rhinovirus infection leading to infection and asthma exacerbation. Mouth breathing caused by nasal obstruction resulting in bronchospasm to cool dry air. Pulmonary aspiration of nasal contents transferring mediators J Allergy Clin Immunol 2001;108:S147-336.

AR, Sinusitis, Asthma: The link Common Triggers and Pathophysiology Anatomy/ Physiology Upper and lower airways are contiguous Functional linkage – nose vs mouth breathing Similar histology(epithelial, neural, vascular) Same mediators IgE Histamine Cytokines Leukotrienes Same triggers HDM, pollen, pet dander, moulds, fungi Same drugs Anti IgE ? Steroids(ICS/ INS) Antihistamines ? Antileukotrienes ? Allergic Rhinitis Same cells Mast cells Eosinophils Asthma Sinusitis J Allergy Clin Immunol 2001;108:S147-336.

AR and Otitis media in children OME refers to a non infectious condition of the middle ear, usually accompanied by Eustachian tube dysfunction with accumulation of serous fluid Allergy as a risk factor for OM* Atopic children more susceptible to both symptomatic AOM & asymptomatic OME* 40-50 % of children > 3 years with chronic OM have confirmed AR** Presence of higher levels of IgE or ECP in the middle ear of allergic children than levels found in the serum at the same time*** In the minds of both patients and physicians, drowsiness has always been associated with medications that control allergic illnesses such as allergic rhinitis and allergic dermatoses. This is because the first generation antihistamines, which ruled the practice from 1950s to 1980s, invariably induced drowsiness. In addition, they had atropine-like action that was responsible for certain side effects. The second-generation antihistamines included astemizole, cetirizine and loratadine. These were free from atropine- like side effects. Further, their potential to cause sedation was also low. Terfenadine was the first of the second-generation antihistamines that was non-sedating. However, its use got curtailed because of some unforeseen adverse reactions: if given along with drugs such as erythromycin and ketoconazole, it could sometimes attain high plasma levels and produce serious cardiac dysrhythmias. So the search continued – for compounds that would be truly non-sedating and also devoid of any adverse effects on the heart. Allegra is the culmination of this quest and perhaps deserves the designation “third generation antihistamine” *Doyle et al. Curr Opin All Clin Immunol 2002 **Fireman et a., JACI 1997 ***Bernstein et al. Otolaryngol Head Neck Surg 1985 1

AR and Otitis Media: Pathophysiology Relationship between nasal allergic inflammation and otitis media is caused by a dysfunction of the Eustachian tube There is anatomic continuity in the form of Eustachian tubes connecting Pharynx and Middle ear Allergic Rhinitis Inflammation Viral URTI Mucosal swelling Obstruction of Eustachian tubes Chronic OME Increased negative pressure and impaired ventilation in middle ear Aspiration of fluids in middle ear during transient openings Acute Otitis media

Complications of AR with Chronic OME Chronic middle ear effusions may lead to hearing deficit and speech impairment in children 519 children with Chronic MEE attending a pediatric allergy clinic reported that 98% had associated nasal allergy A study of children with seasonal ragweed pollen allergy found an increase in the rate of ETO and clinically significant hearing loss compared with pre-seasonal assessment in the same group of children Children with AR, in addition to having MEE and hearing impairment may have a characteristic hypernasal quality to their voice and has potential to affect speech development. In the minds of both patients and physicians, drowsiness has always been associated with medications that control allergic illnesses such as allergic rhinitis and allergic dermatoses. This is because the first generation antihistamines, which ruled the practice from 1950s to 1980s, invariably induced drowsiness. In addition, they had atropine-like action that was responsible for certain side effects. The second-generation antihistamines included astemizole, cetirizine and loratadine. These were free from atropine- like side effects. Further, their potential to cause sedation was also low. Terfenadine was the first of the second-generation antihistamines that was non-sedating. However, its use got curtailed because of some unforeseen adverse reactions: if given along with drugs such as erythromycin and ketoconazole, it could sometimes attain high plasma levels and produce serious cardiac dysrhythmias. So the search continued – for compounds that would be truly non-sedating and also devoid of any adverse effects on the heart. Allegra is the culmination of this quest and perhaps deserves the designation “third generation antihistamine” Lack G. J Allergy Clin Immunol 2001;108:S9-15 1

AR & obstructive sleep apnea Children with AR usually have lymphoid hypertrophy, particularly evident in the cervical lymph node chain & adenoids One study from an otolaryngology department found an association between tonsillar hypertrophy and AR. Only 8% of children in 6th grade without tonsillar hypertrophy had AR, whereas AR was apparent in 29.7% of children with tonsillar hypertrophy Children with AR often become mouth-breathers and snore at night as a result of nasal obstruction and adenoidal hypertrophy The pediatrician must consider the possibility of AR in the assessment of snoring children In the minds of both patients and physicians, drowsiness has always been associated with medications that control allergic illnesses such as allergic rhinitis and allergic dermatoses. This is because the first generation antihistamines, which ruled the practice from 1950s to 1980s, invariably induced drowsiness. In addition, they had atropine-like action that was responsible for certain side effects. The second-generation antihistamines included astemizole, cetirizine and loratadine. These were free from atropine- like side effects. Further, their potential to cause sedation was also low. Terfenadine was the first of the second-generation antihistamines that was non-sedating. However, its use got curtailed because of some unforeseen adverse reactions: if given along with drugs such as erythromycin and ketoconazole, it could sometimes attain high plasma levels and produce serious cardiac dysrhythmias. So the search continued – for compounds that would be truly non-sedating and also devoid of any adverse effects on the heart. Allegra is the culmination of this quest and perhaps deserves the designation “third generation antihistamine” Lack G. J Allergy Clin Immunol 2001;108:S9-15 1

ARIA workshop and children The prevalence of seasonal allergic rhinitis is higher in children and adolescents than in adults Varied prevalence of rhinitis across the world 0.8% to 14.9% (6-7 years ) & from 1.4% to 39.7% (13-14 years) Significant correlation between asthma & rhinitis in school going children During the ragweed pollen season, 60% of children developed Eustachian tube obstruction Gastro esophageal reflux can be associated with rhinitis, especially in children J Allergy Clin Immunol 2001;108:S147-336.

Long term treatment is more effective than on demand treatment ARIA workshop: Recommendations Patients with persistent rhinitis should be evaluated for asthma Patients with persistent asthma should be evaluated for rhinitis A strategy should combine the treatment of upper and lower airways in terms of efficacy and safety Oral H1 antihistamines are the mainstay for management of Mild Intermittent Mild Persistent AR Moderate to severe Intermittent AR Long term treatment is more effective than on demand treatment

ARIA workshop: Therapeutic options Allergen avoidance indicated when possible Pharmacotherapy Safety, effectiveness easy to be administered Immunotherapy Specialist Rx, may alter the natural course of the disease costs Patient's education always indicated

Therapeutic options for AR Hadley JA. Med Clin North Am. 1999;83:13-25. 16. Busse WW. Clin Exp Allergy. 1996;26:868-879.

Step ladder treatment of AR: ARIA mild intermittent persistent moderate severe Allergen and irritant avoidance Immunotherapy Intra-nasal decongestant (<10 days) or oral decongestant Local cromone Intra-nasal steroid Oral or local non-sedative H1 blocker J Allergy Clin Immunol 2001;108:S147-336.

Management of Allergic Rhinitis: ARIA

ARIA : Treatment in children Long-term continuous treatment with H1-antihistamines may improve lower respiratory symptoms and may exert a prophylactic effect on asthma onset in children Seasonal allergic rhinitis per se may affect learning ability and concentration. Treatment with classical antihistamines often had a further reducing effect upon cognitive function. Use of TRULY non-impairing H1-antihistamines may improve learning ability in allergic rhinitis

Indirect Medical Costs Intangible Medical Costs Impact of AR on socio-economic costs Direct Medical Costs Physician Visits Procedures Hospitalization Medication Indirect Medical Costs Lost days of work Decreased productivity School days missed Intangible Medical Costs Quality Of Life Issues Psycho-social aspect of the disease Impairment at work / school Side effects of OTC Fergussan B. OCNA Suppl. Feb 1998

Effect of AR on pediatric QOL School absences & poor performance due to distraction, fatigue & irritability Poor interaction & labeling by peers and embarrassment, isolation and low self esteem Adverse effects of most of antihistamines and decongestants Adverse impact on parents QOL Anxious, overprotective, work absences, family social life, etc.

Urticarial rash & Angio-oedema A transient erythematous skin eruptions due to oedema of the dermis, associated with itching. (Wheal & Flare rashes) or Hive Angioedema Transient swellings of deeper dermal, subcutaneous and submucosal tissues. Angioedema accompanies urticaria in approximately 50% of adults and 80% or more of children