INTRODUCTION
Atopic dermatitis (AD) is a common and chronic inflammatory skin disease characterized by intense pruritis, recurrent eczematous lesions, xerosis, and lichenification. 1,2 Although primarily recognized as a childhood disorder, starting in infancy and affecting up to 20% of children, AD is also prevalent in adults. Some adults may develop new-onset AD, while others may have recurrence of childhood AD symptoms that had shown remission. Using the strictest diagnostic criteria (age of onset <2 years old), a recent study indicated that the prevalence of AD among adults in the United States (US) is 7.3%.3 In another study it was found that approximately 25% of adults with AD in the US have severe disease.4
Several sets of diagnostic criteria for AD have been described in recent decades; none are used universally, and each varies in the diagnostic features given prominence, thus precluding comparability between epidemiological studies.
The objective of this review is to describe the current thinking on the clinical features of AD alongside current treatment guidelines, in order to consolidate and distill past and current criteria used in AD diagnosis, and thereby propose a more simplified set of diagnostic criteria.
Clinical Features and the Diagnosis of AD
In the absence of a definitive laboratory test, a diagnosis of AD is made based on the presence and distribution pattern of lesions with specific morphologic features, associated clinical findings, and a personal or family history of atopy. Clinical features typically present are listed in Table 1.5
Many of the more recently described clinical features of AD such as baseline ocular features, periorbital dermatitis, and prurigo/ prurigo nodularis2,6,7 are now considered to hold greater clinical significance than previously assumed yet are lacking in older criteria that are still in routine use.
Further complicating a confirmed diagnosis of AD with a given set of criteria is the fact that several of the clinical features used in diagnosis are heterogeneous in nature, varying by global region and age.2 Furthermore, phenotypic differences exist between adult- and childhood-onset AD; for example, a US study suggests that those with adult-onset AD are more likely to have been born outside of the US, have less atopy, and a predilection for hand, head, and neck rash than children with AD.7 Such phenotypic differences should be considered in both diagnosis and when assessing disease severity.2
Current and Past Diagnostic Criteria
Hanifin–Rajka Criteria
The most widely used and recognized criteria for the diagnosis of AD are the Hanifin–Rajka criteria, introduced in 1980,8 which remain one of the primary criteria used in the hospital setting today. This model mandates that at least 3 of 4 major
Several sets of diagnostic criteria for AD have been described in recent decades; none are used universally, and each varies in the diagnostic features given prominence, thus precluding comparability between epidemiological studies.
The objective of this review is to describe the current thinking on the clinical features of AD alongside current treatment guidelines, in order to consolidate and distill past and current criteria used in AD diagnosis, and thereby propose a more simplified set of diagnostic criteria.
Clinical Features and the Diagnosis of AD
In the absence of a definitive laboratory test, a diagnosis of AD is made based on the presence and distribution pattern of lesions with specific morphologic features, associated clinical findings, and a personal or family history of atopy. Clinical features typically present are listed in Table 1.5
Many of the more recently described clinical features of AD such as baseline ocular features, periorbital dermatitis, and prurigo/ prurigo nodularis2,6,7 are now considered to hold greater clinical significance than previously assumed yet are lacking in older criteria that are still in routine use.
Further complicating a confirmed diagnosis of AD with a given set of criteria is the fact that several of the clinical features used in diagnosis are heterogeneous in nature, varying by global region and age.2 Furthermore, phenotypic differences exist between adult- and childhood-onset AD; for example, a US study suggests that those with adult-onset AD are more likely to have been born outside of the US, have less atopy, and a predilection for hand, head, and neck rash than children with AD.7 Such phenotypic differences should be considered in both diagnosis and when assessing disease severity.2
Current and Past Diagnostic Criteria
Hanifin–Rajka Criteria
The most widely used and recognized criteria for the diagnosis of AD are the Hanifin–Rajka criteria, introduced in 1980,8 which remain one of the primary criteria used in the hospital setting today. This model mandates that at least 3 of 4 major
