Abstract and Introduction
Background: Eczema and atopic dermatitis (AD) are recognized as major health problems worldwide. Prevalence estimates are as high as one-third of the population, depending on the country studied, the age range of the subjects, and the diagnostic criteria used. National estimates of prevalence for the US population are lacking.
Objective: To examine the public health problem posed by eczema, AD, and eczematous conditions in the United States by analyzing disease and symptom prevalence, estimating the number of undiagnosed cases, and assessing comorbidities.
Methods: A self-administered questionnaire was sent to a sample of households (N = 60,000) representative of the US population. A designated member responded with information on symptoms, diagnoses, and impact for affected household members; 42,249 households (70%) responded, representing 116,202 individuals. Empirical eczema was defined by itching/scratching and red/inflamed rash or excessive dryness/scaling. Empirical AD was defined by itching/scratching and red/inflamed rash, excessive dryness/scaling, skinfold location, early onset, symptoms lasting ≥ 14 days, or a physician diagnosis of asthma or of allergic rhinitis or hay fever.
Results: Of the population studied, 17.1% reported at least one of four eczematous symptoms; empirically defined eczema was found in 10.7%, and empirically defined AD was found in 6%. Prevalence decreased with increasing income. Approximately two-thirds of individuals with an empirical diagnosis of eczema or AD had moderate to severe symptoms, one-third had sleep disturbances, and one-quarter had chronic unremitting symptoms. Just over one-third (37.1%) of those with symptoms reported a physician diagnosis. Peak onset for empirical AD occurred in the group of subjects aged ≤ 5 years. For empirical eczema, peak onset occurred in the group aged 18 to 29 years, and comorbid asthma and hay fever/allergic rhinitis were more prevalent.
Conclusions: A substantial proportion of the US population has symptoms of eczema or eczematous conditions; 31.6 million met the empirical symptom criteria for eczema, and 17.8 million met the empirical criteria for AD. Most cases are not diagnosed by a physician, which indicates that these conditions are undertreated and/or managed with nonprescription remedies.
Eczema is a disease group or genus that encompasses a number of forms of dermatitis, both endogenous (atopic dermatitis [AD]) and exogenous (eg, irritant and allergic contact dermatitis). The term "eczema" is often used by nondermatologist physicians and the lay public to signify AD. Characterized by varying degrees of erythema and itching, eczemas include (in addition to AD) several disorders such as contact dermatitis, nummular eczema, and seborrheic dermatitis, all differentiated by their etiologic factors, morphology, or patterns of distribution. AD is a chronic condition that usually begins in the first few years of life and tends to appear on the face and in the skinfolds of the arms and legs. Although its cause is not known, AD is often associated with a personal or family history of asthma or hay fever/allergic rhinitis.[2,3]
Although not life threatening, eczema can result in disability, especially when the hands or feet are affected. Occupational eczema is a prominent form of work-related illness. In many patients, the constant scratching and rubbing may lead to skin damage and secondary infection. The condition also has a significant impact on the quality of life of the individual and his or her family. In fact, caring for a child with moderate or severe AD has a significantly greater negative impact on the family than does caring for a child with diabetes, and the financial costs incurred by the family are greater than those incurred by the family of a child with asthma. The costs of therapy, work loss, and disability from the eczemas can only be roughly estimated. A recent study of AD estimated that direct costs alone were $1 billion to $4 billion (US) in the United States.[6,7]
Despite the fact that eczema and AD are major public health problems worldwide, few epidemiologic data exist for randomly selected samples of the general US population. A national health survey performed in the United States in 1977 found the prevalence of AD to be 7 to 24 per 1,000 population. Data for eczema in randomly selected samples of the general populations of the Netherlands, the United Kingdom, a rural Japanese district, and Danish women (hand eczema) indicate prevalence rates of 7.1%, 6%, 26%, and 18.8%, respectively.
Prevalence data for AD, specifically, indicate rates of 7 to 21% among children across various countries.[13,14,15] A survey of schoolchildren in Oregon suggested a prevalence of 17.2%. A cross-sectional survey of adults in Japan showed a lifetime prevalence of 3.3%. The International Study of Asthma and Allergies in Childhood determined that the 1-year prevalence of AD among the children of 56 countries ranged from < 2% in Iran to > 16% in Japan and Sweden, and there were generally higher levels in the more northern latitudes. These figures contrast with a 1955 survey of children less than 5 years of age (but more than 1 year of age) from Bristol, United Kingdom, that showed an incidence of eczema of 3.1%. These older data must be interpreted in light of apparent increases in the prevalence of AD and eczema that have been noted during recent decades in the industrialized world.[3,13] Current data for AD across the United States as well as data for the eczema composite are needed.
In the present study, the magnitude and demographic distribution of the public health problem posed by eczema and AD in the United States are described, with data from a nationwide sample of more than 42,000 responding households. The survey covers all age ranges and all regions of the United States and assesses comorbidities, symptoms, and self-rated severity. This report contains the first data on the prevalence of eczema and AD in the general US population and highlights the need for improvement in the identification and treatment of patients with eczematous conditions.
Dermatitis. 2007;18(2):82-91. © 2007 American Contact Dermatitis Society
Cite this: A Population-Based Survey of Eczema Prevalence in the United States - Medscape - Jun 01, 2007.