Background: There are infrequent or unspecific diseases that occupy an important part of time in the job of the allergists.

Objective: We sought to evaluate the frequency and to determine the characteristics of uncommon or unspecifi c diseases seen by allergists in Spain, and to compare these data with findings obtained in a similar study undertaken in 1992.

Material and Methods: An observational, prospective and cross-sectional study named “Alergológica 2005” was carried out in Spain. A part of this study analyzed the demographic, healthcare and clinical aspects of infrequent or unspecific diseases categorized as “Other allergic diseases” (OAD) or “Other non-allergic diseases” (ONAD).

Results: The survey comprised 4991 patients. In OAD, 45 patients were included. In ONAD, 290 patients were included. Significant diagnoses were gastroallergic anisakiasis (10 patients), idiopathic anaphylaxis (7 patients), and hypersensitivity pneumonitis (2 patients). In the ONAD group, non allergic respiratory diseases were the most frequent diagnosis. Mean time spent to reach a diagnosis was 14.2
days. However, the median of this time was only 1 day. Main diagnostic methods employed were a clinical history/physical examination in 86% of patients and skin tests in 73.7%.

Conclusion: Several unspecific diseases affected more than 60% of patients in the two groups together. Findings show the current knowledge of allergic disorders due to Anisakis simplex. Diagnoses of hypersensitivity pneumonitis seem to be as frequent as previously published. Idiopathic anaphylaxis seems to be less frequent. The wide-range of times needed to reach a diagnosis was in agreement with the mixture of diseases included in both groups.

Key words: Allergy. Epidemiology. Cross-sectional study. Other allergic diseases. Other non-allergic diseases. Gastroallergic anisakiasis. Hypersensitivity pneumonitis. Anaphylaxis. Alergologica.