[Cutaneous reactivity to common ivy (Hedera helix) pollen extract in allergic patients].

Background: Common ivy is an ubiquitous ornamental plant found indoors and outdoors. It may cause occupational contact dermatitis and asthma. Many traditional and naturistic preparations may contain their extracts, hence sensitization may occur by several routes.

Objective: To determine the prevalence of sensitization to Hedera helix pollen by skin prick test on allergic subjects.

Methods: Skin prick tests (SPT) with 24 pollen extracts, including Hedera helix extract, were performed on 62 patients with allergic rhinitis, asthma, allergic conjunctivitis and atopic dermatitis. It was determined the frequency of sensitization to pollen extracts and the differences in the reactivity patterns among patients who showed a positive or negative result with Hedera helix extract. A cluster analysis was made to identify cross-allergenicity among pollen extracts.

Results: Eleven out of 62(17.7%) patients had a positive SPT with common ivy pollen extract. The main differences found were the number of pollen species to which patients were allergic. Patients with atopic dermatitis had a nine-fold higher frequency of positive skin tests with Hedera extracts, than subjects with other allergic diseases.

Conclusions: Hedera helix pollen extract is a frequent cause of sensitization among allergic patients, and show cross-allergenicity with pollen from different sources. There is a higher frequency of positive skin tests with Hedera extract in patients with atopic dermatitis than with other allergies.