Long-term follow-up of atopic dermatitis: retrospective analysis of related risk factors and association with concomitant allergic diseases.

BACKGROUND: The association of atopic dermatitis (AD) with other allergic diseases has been extensively studied; however, there is a lack of reports focusing on long-term studies of the clinical and allergometric evaluations observed during the course of AD in respect to its evolution and association with allergic responses in affected patients.
OBJECTIVE: The aim of this study was to evaluate, with defined criteria of clinical diagnosis, severity assessment, and objective allergometric test at the time of inclusion, the natural course of AD, the factors influencing its healing or persistence, and the appearance of other allergic diseases with particular focus on asthma and the presence of specific immunoglobulin E at first observation.
METHODS: This study included only children, aged between 6 and 36 months, whose first clinical examination was made between 1981 and 1989. A total of 252 children satisfied these criteria. A semistructured interview was performed by the physician using a preformed questionnaire, which was completed for 205 children (104 boys and 101 girls).
RESULTS: AD had completely disappeared in 124 cases (60.5%). Other allergic manifestations that appeared included asthma in 70 cases (34.1%) and rhinoconjunctivitis (RC) in 118 cases (57.6%). Generally the average age of patients recovering from AD was higher in severe AD (6.0 +/- 3.5 years) than in its moderate or mild forms (5.8 +/- 4.5 and 5.5 +/- 3.9 years, respectively). This phenomenon was particularly evident in children with hen's egg sensitization, who show a longer persistence of the condition (Student t = 2.462 and P < .02). The initial severity score of AD was found to be associated with a high frequency of asthma appearance (Pearson chi2 = 14.225 and P < .001). Hen's egg sensitization was significantly related to the appearance of asthma (Fisher's exact test P < .007) and RC (Fisher's exact test P < .05). A retrospective analysis of related risks factors and their association with concomitant allergic diseases in our case studies shows that the egg sensitization, severity of AD, and onset of RC were positively related to the occurrence of asthma. In addition, our analysis shows that, although the appearance of RC was proportional to the incidence of atopy and asthma, it was inversely related to the persistence of AD (corrected odds ratio confidence intervals <1). LIMITATIONS: The study includes children referred to the hospital. However, it is the practice of local national health pediatricians to send all patients with suspected AD, whatever the severity grade, to hospital specialists to perform allergometric assessment.
CONCLUSION: The use of defined criteria of clinical diagnosis for the determination of the condition's severity, along with the performance of objective allergometric tests at the time of inclusion, shows that the course of AD is significantly related to egg sensitivity. In addition, the average healing time is higher in egg-sensitive patients affected by the most severe form of AD than in mild or moderate cases.