Recent epidemiological and genetic studies in atopic dermatitis.

In a prospective computerized study, basic and minor features of atopic dermatitis were studied systematically in established cases of atopic dermatitis (AD; n = 428) and compared with subjects randomly collected from the caucasian normal population of young adults (NP; n = 659). Complete genetic data (history of AD, allergic rhinitis, allergic asthma) were obtained from the first-degree relatives of all subjects (about 9,000 family members). In young adults, atopy was found in 22.5% (AD 4.7%, allergic rhinitis 17.9%, allergic asthma 4.8%). Of 428 AD patients, 54% had 'pure' AD and 46% suffered from a 'mixed' type with concomitant respiratory allergies (RA). The general risk of developing AD and atopy increases with each first-degree family member already suffering from atopy. Our study further supports the evidence of a genetic influence on symptom specificity. Risk figures for genetic counselling are given. The complex interplay of atopic symptoms and signs in the diagnosis of AD has been analysed by a CART analysis. Compared with non-eczematous controls, the odds ratios (OR) of frequent features in AD are as follows: xerosis (OR 27.9, 95%-CI 23.2-33.8), itch when sweating (OR 25.4, 95%-CI 21. 1-30.1), white dermographism (OR 19.3, 95%-CI 16.2-23.2), wool intolerance (OR 15.8, 95%-CI 13.40-18.5), whereas the OR of elevated IgE (> 150 U/ml) was only 5.0 (95%-CI 4.3-5.8). But when comparing the AD patients with concomitant RA separately, the odds ratio is increased to 16.2.