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Wise et al.

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symptoms in 257,800 children aged 6 to 7 years in 91 centers in 38 countries and 463,801 children aged 13 to 14 years in 155 centers in 56 countries. Although the ISAAC survey was not validated for the diagnosis of AC, ISAAC studies support the frequent association of AR with itchy-watery eyes, reporting that ocular symptoms affect approximately 33% to 50% of children with AR 1883 (Table X.C). The best evidence of disease-association derives from studies of AR patients assessed for the prevalence of AC as a comorbidity. 1884-1890 The evidence suggests that AR is associated with 35% to 74% prevalence of AC and that among patients with AC, the prevalence of AR may be as high as 97%. To summarize, there is a substantial body of evidence which supports AC as a frequently occurring comorbidity of AR, particularly in children. Not only is this disease-association common, but ocular allergy symptoms also contribute significantly to the QOL impairment associated with AR. It is not surprising, therefore, that ocular symptoms of allergic rhinoconjunctivitis are among the most common symptoms which cause patients to seek allergy treatment. 1891 It is advisable, when assessing patients with AR, to also assess for ocular symptoms and to consider treatment specific to providing relief of AC. • Aggregate Grade of Evidence: C (Level 2b: 2 studies; Level 3a: 2 studies; Level 3b: 3 studies; Table X.C). AD is a chronic and/or relapsing skin disorder characterized by pruritus, scratching, and eczematous lesions. 1892 Its burden of illness, impact on QOL, and complications are substantial. 1893 AD commonly presents as the first manifestation of atopy in infants and children who later develop AR and/or asthma, a pattern that has been referred to as “the atopic march.” 1894 Although the association between AR and AD has long been clinically recognized, the extent of this association remains poorly defined due to methodologic differences and limitations of the studies that have examined this association 537,556,636,1895-1912 (Table X.D). Further compounding this problem is the phenotypic diversity of both AR and AD, and the observation that very few studies have adequately characterized the phenotypes of their study populations. Additionally, many epidemiologic studies are limited by being based purely on questionnaire results rather than objective evidence of allergic sensitization, such as SPT or in vitro testing. The largest data source regarding AR-AD association comes from the ISAAC study, investigating the epidemiology and etiology of asthma, rhinitis, and AD using standard methodology including questionnaires, SPT, and flexural dermatitis examination. 1895 ISAAC reported the prevalence of AD symptoms in 256,410 children aged 6 to 7 years in 90 centers from 37 countries, and 458,623 children aged 13 to 14 years in 153 centers from 56 countries. These studies indicate that AD is a major public health problem worldwide, affecting approximately 5% to 20% of children aged 6 to 7 and 13 to 14 years. 1896 While longitudinal studies demonstrate improvement or resolution of AD with age, 1897 increasing

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X.D. Atopic dermatitis (AD)

Int Forum Allergy Rhinol . Author manuscript; available in PMC 2020 June 10.