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Allergen‐induced hyperreactivity is not a feature of dermal immediate allergic reactions—in contrast to reactions of airways mucosa

Allergen challenges of airway mucosa are commonly followed by an increased sensitivity to rechallenge with allergen. In the lower airways this phenomenon has been associated with the late phase of allergic airway reactions, which in turn has been suggested as a link between anaphylaxis and continuous allergic airway disease. The aim of the present investigation was to explore further the phenomenon of allergen‐induced hyperreactivity and to see whether it was possible to induce such a reaction in the skin. Twenty‐six patients with seasonal allergic rhinitis due to birch and/or grass pollens were studied in the pollen‐free winter months. Nine of these patients had previously demonstrated an increased reactivity following allergen challenge in the nose, and nine of the patients had cutaneous allergen‐induced late‐phase reactions to the allergen tested. Skin‐prick tests were performed with pollen allergen, histamine, and a negative control. The areas of the weal‐and‐flare reactions were measured 15 min after the tests were set. Any late‐phase reactions were recorded 6 hr after the skin challenge. The subjects were re‐tested with allergen and histamine 24 hr after the initial prick test within the area of the corresponding weal from the previous day. In contrast to previous challenges of human airway mucosa. where the same time interval was used, we found no increased responsiveness to rechallenge as compared with the initial allergen challenge. This was true, even if only the subgroups with previously demonstrated nasal allergen‐induced hyperreactivity. or cutaneous late‐phase reaction were evaluated. It is. therefore, suggested that allergen‐induced hyperreactivity as a feature of allergic airway mucosa may be related to changes in the epithelial barrier function.