Background  Urticaria is often underdiagnosed and/or undertreated. We have conducted an Internet-based study to record epidemiological and clinical features as well as therapeutic interventions for urticaria in a large sample of patients in Greece.

Methods  A standard anonymous questionnaire was posted for a 3-month period on ‘http://www.in.gr’, a Greek popular Internet portal. Each individual participated only once. Participants were screened for the presence or history of urticaria by two key questions and were then asked to provide information on symptomatology and management.

Results  A total of 12 396 subjects voluntarily responded to the survey, of which 8440 (5136 females) who reported to have or had urticaria, were finally analysed. A total of 4780 (56.6%) had experienced weals only, 507 (6.0%) angio-oedema only and 3018 (35.8%) both. Weals and angio-oedema were found to be more common in women; 2761(57.8%) and 277(54.6%), respectively. Age of onset significantly correlated with disease duration; a 1% higher possibility of longer duration of urticaria exists (more than 6 weeks compared with less than 6 weeks) for each additional year of age of onset after controlling for gender. Patients with chronic urticaria had increased mean age compared with those reporting the acute form (35.04 vs. 33.88 years, P < 0.001). Dermatologists were the most frequently visited specialists and the most common treatments were antihistamines and topical preparations. The self-reported eliciting factors of urticaria were as follows: physical stimuli (approximately 25%), psychological distress (17.2%), direct contact to metals or chemicals (14.5%), foods and drugs (10%), whereas a third of the participants could not identify any trigger.

Conclusions  Internet surveys can be a useful tool for screening the general population for common allergic disorders, such as urticaria.